10. When people touch my mixing board or audio gear. You can blow up a speaker or amp or potentially damage someone's hearing. This is expensive equipment so if you don't own it, don't touch it and keep your drinks away from it.
9. When bands ask me to turn the monitor up. Each monitor is a separate mix. Tell me what instrument or vocal you want to hear in the monitor and I will turn that up for you.
8. When bands tell me they want to hear everything in the monitor. If I put everything in the monitor it's just going to sound like mud because it's a mono mix and everything is on top of each other. How about you tell me the two or three things that are most important for you to hear and we'll start there.
7. When bands don't bring what they need to play the show. If you need adapters, cables, batteries, etc to make your equipment work, bring it and bring backups. If you break a guitar string, the show can't end because of it. If you need a special adapter don't expect me to have it. Although you might get lucky and I do.
6. When bands ask the crowd how it's sounding out there. That's insulting. I do this for a living.