Teleporting into lava is fine ... so long as they know to do it to you too.
But... then my super awesome character will die in the lava and be unrecoverable!!!111
In a typical D&D game where enemies can do things like that to you as well, it's devolves into a bunch of bullshit non-combat combat and people soon say to the DM that this type of gameplay isn't fun (or the DM figures it out without player input). In the game format it's permanent game over for one of the characters, which is why it shouldn't really be in the game at all - either you make the enemies copy your tactics and make the game unplayable or you make the enemies beyond dumb and thus the combat is a pointless series of buttons you need to press to win. If I wanted to not have to bother with combat myself I'd read a book or watch a movie... or maybe played a different sort of game.
Sorry, I didn't want this to seem like an attack at you, I just wanted to make sure people knew I was talking about teleport into lava BS.
