Depend in on platform they aren't insignificant. I really wish you'd look around before talking. I spend everyday that I play borderlands also talking with the community.
1. BNK-3R will cause a game freeze during death animation sometimes
2. Game will freeze if you try to re-enter the warriors room after killing him sometimes.
3. Randomly at any point on any of your saves all your BA rank and skins/heads will be wiped and you will be unable to reacquire them
4. Small, lighter, faster will reduce an infinity weapons magazine to 0. Making all guns of that type useless for mechro.
5. Keep it pipping does nothing.
6. In multiplayer one mechro losing anarchy due to prematurely reloading might make all mechros in the group lose anarchy.
7. Using quest filtering on PC will cause save files to rapidly increase in size to the point of quick saving freezing the game.
8. Drop tables math is done incorrectly, or at least the whole world feels deceived by it.
9. During gods talon jack may bug and keep his reflective shield after the surveyor is killed.
10. Terramorphous mods will still display after a teammate has picked one up. So if you see a mod but can't pick it up. Someone ninja'd it.
And that's just what I can think of that is actually gameplay pertenant and game ruining.