Is it possible to make a door that doesn't open or close unless you press the use key? I am really fed up getting killed because a door didn't open fast enough, or it closed just as I tried to run through. Maybe I am missing something but doors in real life tend to stay open unless someone closes them :)

Or would it make a map too laggy to make all the doors destructible? Or what about more maps without doors? Call of Duty has no doors and I don't miss them in that game.

In the "wait" field in the func_door properties, giving it a value of -1 will make the door stay open. Also, checking the "toggle" will let the door be opened with the use key.

Thank you very much for the reply, just what I was looking for. However I am not a mapper I just wanted to request someone to do this and now there is no excuse :) Hell I might even take up this lark just because I hate them so much.

I find it insane that it is taken by default that doors close automatically behind you. Unless this makes for faster maps and higher fps?

Well Windy, I have a suspicion that mappers use this for
a couple of reasons.
It makes a noise every time someone passes through the door
so that oponents near can sort of get a feeling for when someone
is comming.
It limits owning the doorways by proneing with a MG42, wich would make such a spot a bottleneck.
It allso in general limmits the stream of players comming through that aeria, at least some, like you who hate it. :D
That's my guess anyways, but I totally agree, it's mostly annoing,
but a part of the gameplan I think. ;)