Personally I treat E-mail as a letter so it sometimes takes me quiet a while to answer them.
The thing that anoys me the most is it's so easy for unthinking people to hit the forward button and bombard you with junk. The ones that anoy me the most are the ones that end with "if I don't get this back........" I dump all of them as I don't like the emotional blackmail they are loded with. If there is a good mesage in them or some enjoyable pictures why carn't the sender deleat the rubbish at the end then send.