I'm looking at Fallout 3 and New Vegas here.

My first time playing FO 3, almost every time I came home to Megaton, Deputy Weld(?) was fighting Giant Ants. I would come home and help him out if he needed it and when I left, usually the next day, I would help him again.

The next 2 times I played, I think he had an "ant attack" once each game.

In New Vegas, When left Goodsprings and headed towards Primm, Geckos were everywhere. They were in the ditches, on the road, crossing the road by the ditches, all over the place. I went through so much ammo that first playthrough, I wondered what I would do for the rest of the game!

My next 2 times, I either did not see them, or they just were not there. I looked, I did!

It seems that some games seem to get stuck in a certain mode, like spawning Giant Ants all the time, and then when I play again, it is a very different experience.

Anyone else find similar things in games, or is it just my warped mind seeing what isn't really there?

Maybe your stats influence the randomness.

I recently played Fallout 3; each time I arrived at Megaton the ants were dead. Never witnessed any fight. It's probably due to the fact that my characters walk; they never run unless they have to. A habit that came with Skyrim.

Didn't some enemies respawn where their bodies were left behind in Fallout 3? You could drag them somewhere else and they would respawn there.

That could explain the repeat attacks atleast.

It was mostly repeat raider attacks outside of Megaton for me.