PaulS:
They're evil and should be banned from the language.
Evil? No, I don't think so. Bad? Most of the time, yes.
Banned? No, I don't think so. They can almost always be avoided, but there ARE rare cases where they are needed. On an Arduino? I don't think so, but they should not be removed from the C language.
PaulS, of course you're right. But there was a hidden 
at the end of my comment. Too bad I took my hands of the keyboard right before it made it to the screen...