Or, more precisely, don't do these FIVE things when your band plays live! You see, there's this trap that some musicians fall into, and it usually appears either right at the beginning of their foray into the live circuit or after they've gotten about 20 shows or so under their belt - they start buying into all of those rock'n'roll fantasies. Instead of showing up for their soundchecks on time, they role in on their own schedule. Instead of being gracious to everyone involved in promoting their show, they're demanding and diva-like. The list goes on.
These things are a bad look for a number of reasons. First of all, if you're doing them, your lack of professionalism will make you look pretty foolish, and people will be talking about you. Second, they're surefire ways to make sure you never get booked again. The music industry is a small place. Get a bad reputation, and that slowly-building network of promoters and venues you've put together with disintegrate in a hurry. After all - remember the golden rule of the music industry - you CAN and WILL be replaced.
So, with that in mind, please skip these bad habits the next time your band plays live. Promoters and venues, if you have some to add, please share!