1) the service leader will give you the powerpoint (or similar slides 2 minutes before the service starts and then glare at you accusingly when:
a) they move on automatically because they are on a timed presentation;
b) the hymn words miss a verse or chorus or both or are in the wrong order;
c) the text is unreadable cause its too small and or the wrong colour font on the wrong colour background.
What not to say - Hey Bill - your slides don't seem to be properly prepared - I guess you screwed up huh?
2) the service leader seems incapable of switching their microphone on when they want to speak - or turning it off when they don't want their speech to be heard;
a) despite the fact before the service they said they were fine with mics
b) know now that frantic signals of hands to ears won't communicate the mic isn't on;
c) the best approach is to go up during a hymn and explain what they are doing wrong - but make it a really long explanation that lasts most of the hymn - believe me - leaders don't like an obvious "how dumb are you" conversation play acted in front of their congregation;
What not to say - from the control desk at the back on the PA mic - turn the f*?!!$$'g mic on/off Bill
3) there is that moment when the video clip or slides or music clip really don't fit in with where the mode of the spirit in the worship has taken you - so don't use it ......
What not to say - but that wasn't on the programme