Rules: (They're easy and painless)
1. I have far better things to do than throw tantrums/stalk people if I don't get credit, however, credit is of course always appreciated. Just don't steal my work; it's not yours. (Or, as the seagulls in "Finding Nemo" say: "Mine! Mine! Mine!")
2. Do not ASK if you can have the icon. Sorry, but I have neither the time nor the patience to answer every "May I" with a "Yes." Comment if you get the chance and let me know what you're taking, and that will suffice.
3. Sometimes, the server acts up and the icons can't be viewed for an hour or so. One comment alerting me to this (not that I can do anything about it) is fine; five are not. If you can't see them, be patient and they'll hopefully show up within the hour. In the meantime you can always help yourself to my user icon.
See? I told you that would be easy and painless!