Most definitely it is just that.

Well, in StarCraft 64, I would frequently (especially in skirmishes) try to get into a nice, defensible situation where I had control of as many of the resources as I could manage, then basically just milk the map for all the resources I could harvest, never quite finishing off the enemy AI (or completing the final mission goals, if it was a story mission) until I had stripped the entire area of everything valuable.
Not so much "absurd" as "tedious", though. :P

Also, like NoNewTaleToTell, I've spent countless hours farting around in various PS2 GTA titles over the years. Among other things (many, many other things), I always enjoyed observing/causing crashes. I don't think it was quite so much of a problem in GTA III and Vice City, but in San Andreas, with its miles of freeways and highways, vehicles often moved at absurdly high speeds, but they also tended to (try to) stop on a dime...which usually didn't work out well for the vehicle(s) following them. This could lead to some hilarious pile-ups, and due to how explosion-prone most vehicles were in those games, there could be some spectacular chain reactions. Often, for one reason or another, I'd wind up on foot on or alongside a stretch of freeway, waiting for a car to get rear-ended, then that car to get rear-ended, etc., in hopes that eventually one or more vehicles would be battered enough for it to catch fire and explode (if I was REALLY lucky, a car would simply get flipped upside-down somehow, which was a direct route to Splosionville in those games). Once a fire was started on the roadway, I could simply wait for new cars to come along, get stalled behind the burned-out husks of previous unfortunates, and hope that one of the fires would spread to where the car was (assuming they didn't just park in the inferno to begin with!). Standing in the road in front of a honking motorist who's oblivious to the fact that the entire rear of their auto is engulfed in flames, and who only realizes the danger and tries to speed away once their engine's on fire, is really one of the more delightful ways to waste an hour or two. Scooping up the money from the charred bodies of the occupants after their vehicles are done blowing up is just gravy.

Also, repeatedly riding a bike (motor or pedal) off the rooftop helipad of a downtown Los Santos high rise is always good for some shit-your-pants lulz. =)

In Skyrim, I went on a quest of my own to gather interesting books. I would find them, steal them, if some dude or gal sold a book, I would steal it as well. Then I would read all the books I found. You, you can't really tell interesting ones just by looking at the cover. Some were really old and ugly.

Then I would return to my house in Whiterun and try to stack them books in the bookshelf. But that thing couldn't handle any more, so I would just slap it with books eventually and go exploring further. For some time my house looked like a book's junkyard.

Me and my dad would often go 1v1 in RTS games, these would always take hours upon hours and where intense and close matches 90% of the time.

One time we decided to play Dawn of War: Dark Crusade with a no-pop cap limit mod. He was the Space Marines and I was the Orks.

The map was big, and was designed with a bunch of canyons leading all over to different areas. Well I took 80% of the map VERY quickly, forcing my father to build up a defensive line of about 100 or so turrets and at least 400-500 men. By the time my Orks hit his defensive line the entire map was FILLED WITH ANGRY SCREAMING WAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGH!!!!!!!!!!!

It was like a battle out of the LotR movies, just a fucking sea of orks, loot tanks and Squiggoths. It got kinda choppy but holy fuck it was amazing to watch, and to top it all off, he managed to squeeze a small force through the lower half of the map, slip into my base, and completely wreck my shit.

About a year later, we played Company of Heroes, on the map Lyon with a no pop cap mod and the same thing ensued, swarms of my german infantry and tanks trying to cross the bridge in the middle and invade his base, and punch through his line of machinegun turrets, AT guns, mortars, and Rangers. Eventually after oh, 3-4 hours I broke through. Revenge is sweet.

I said Hi to my brother once by spelling it out in dead hookers in one of the Hitman games.

What a coincidence -- I just did that same thing a couple months ago! Well, not exactly the same, I guess. I wasn't saying "Hi" to my brother, but to the cops. And I didn't do a practice run in a video game first, like you did. =)

Now, that's pretty impressive I must admit :)

Morrowind - Pillow fort.

Fallout 3 - Agitating Fawkes. Sometimes his AI would trigger agro, sometimes he'd just scream and run away when you attack him. Funniest bits would be stopping in the middle of nowhere, initiating a conversation with him, then immediately blasting him with a Fatman at point blank range.

DayZ - Probably my favorite multi-player moment. I found a helicopter at Balota and flew it at tree-top level right over the entire southern coast. Several other players on the server actually accused me of using hacks because of my awesome Airwolf level flying skill. I was trying to behead players with my rotor blades when a sniper player took me down with some well aimed shots. My chopper crashed into a building and took out a couple of camping players. The entire chaos only took about 5 minutes, but it was a classic gaming moment for me.

The Sims - Pulling the old 'let sim go into room, then go into editor and remove door' trick. Watching Sims freak out and eventually starve to death while walking in circles... it's a bit mean spirited, but quite entertaining. The same trick can be applied to swimming pool ladders. The sim will just swim around in panic mode until they get exhausted and drown. It's not hard to be sadistic to sims.

As a small kid, playing Munchman for several hours straight (I dunno, was it 5-8 hours or so) because I had become so good at it that I'd get extra lives more often than I'd die, and reaching 1.000.000 points (actually 999.990 I guess)... and actually expecting something marvelous to happen when I do!

Nothing happened, besides the score counter rolling back to 000.000. What a letdown. I stopped playing that game for good after that.

Mafia 1 green pepper censored version i got out the tommy gun and wanted to get a civilian into the water,but only thing it happened is the civilian kept going higher and higher when i was shooting them close to the water until the civilian fell down on the ground she survived everything so i guess it's one of those really tough women.

Having crush on female characters/npcs/enemies. :))

I once lost a game of FreeOrion in just two turns. Did not play it since then.

I figured out how to get rid of the butler in the Croft Manor.  Winston Smith was annoying and creepy in Tomb Raider II !  :-p

One time I started a new game of Wizardry 4 and got ambushed and killed before I could reach the first pentagram (which is right next to where you start).

Another time I started a new game of Wizardry 4 and got ambushed by a thief right away. The thief tried to steal long enough for me to run away. (You start the game at 1 HP and no items; hence, the I had nothing for the thief to steal.)

Another ridiculous thing is how I beat Civilization 3 on Sid difficulty. I created a custom map where every square is mountains (Civ 3 doesn't let you build cities on mountains). I started the game, skipped my first turn (building a city isn't an option because mountains), and the AI just gave up, awarding me a Conquest victory.

I also tried a map containing only water, but the game crashed with a message about not being able to find suitable starting locations for the civilizations.

In Civilization 2, I would use a cheat to set a city's size to 0. That city would disappear when a unit would move next to it, but would still be there. Capturing the city (by moving a unit to that square) would crash the game with an "overflow or division by zero" message. (I think the game tried to give me money equal to 1/0th of the city's worth, with the 0 being the size of the city before I captured it.)

You have written about this earlier here on the forums as I remember reading about it :-) It certainly fits the thread.