No, I don't thing I stole anyone else's job! Though listening to some of the discussions on immigration here in the UK, sometimes I wonder if the politicians might not think I did...

I suppose my guilt has to do with the fact that if they paid me less they could pay people having thankless/boring/what-have-you jobs more. On the other hand, knowing employers, I think they would just pay me less, and the other people less as well, so I usually don't let it get to me (too much).