Well, like the others said, it's not really a nice thing to do. Not only are you skipping work without an acceptable reason (If you had one, you didn't have to lie about being sick), causing others to have to do your work too while you still get paid for it, but it also causes some major problems if you get caught. Your teacher/boss will not only be distrusting towards you, but also towards anyone else with the same excuse, even if it's actually legit for them. So yeah, don't do it :P

...That being said, I would be lying if I said I have never done this in the past for whatever reason >_>.