I hate hitting the wrong key. I can never get the Z key to use my shouts, I always press X by mistake. Very frustrating.

But I always hit 'i' for inventory instead using tab.

If one of the other mobs kills the dragon that you're fighting, do you gain less exp for the kill? You still get the dragon soul and loot of course, but I hate damaging the dragon down to a sliver of health, then losing the finishing hit to a troll.