horus:
You did right by the GM and the other players by withdrawing when you realized what was going on with you.
...Assuming you
told them you were leaving, of course.
GMs are used to drop outs at the start of a game, it's probably no biggie.
The problem for GMs is
not knowing whether a player has left or not - that just wastes their time and everyone else's, while they send out PMs and wait for a response, and hold your place open in case you've had family/work/internet issues.
Those delays and uncertainties spoil the game for everyone.
If anyone is leaving a game, all they need to do is post something like Nowhere Man posted here - it explains their situation, wishes the GM and players well, and makes a clean break that allows the game to continue smoothly without them.
If the GM becomes a jerk over it - well, you've already left the game, what're they gonna do? But by leaving a polite goodbye, you
find out whether that GM is a jerk, instead of leaving them with the impression that
you are.