Nowadays everyone knows about glitches in games and there are a lot of guides on the internet teching how to trigger them and . But has anyone found a glitch unintentionally all by him/herself (without guides or people telling how to do them)? As for me, I can only remember of two, and they are most likely the major ones, or even the only I found out as a kid:
* SNES - James Bond Jr.'s Lost World: I still can't remember how I managed to trigger this one. But I DO remember the effects... Jr. kept falling... falling... falling... doing some strange movements... falling... falling... until landing on some kind of ground with a lot of characters from the game. One of them were even throwing bombs (the one you can throw in the game). I thought this was some kind of easter egg back then...
* PS1 - Diablo's Item Duplication: everyone that played this game knows this glitch, but at the time, I didn't know anything about it. The first time it happened I was like "WTH just happened?". I kept trying to replicate it until learning how to do it... my best discovery so far! It's so good when we find out these things without a guide... Too bad because of this glitch (I guess), my lv.30 warrior got corrupted... twice!

I still find glitches nowadays (rarely), but they're just minor ones that annoy the player, the most recent being in Ocarina of Time 3DS - trying to get up on a block you can push/pull while floating with the hover boots causes the game act like Link fell in a pit, taking some life away and sending him back to the beginning of the room. It's not a big deal, but it's still weird... and annoying! It killed me once!

So what glitches have you found out all by yourself? And what was your reaction?