also - don't be scared to tell your spotter EXACTLY what you want them to do. Tell them how many reps you're going for too.
There is some wild spotting out there that clueless people will do, and a bad spotter is worse than no spotter.
When I get a spot on the bench I always tell them I want a lift off and then they are not to touch the bar again under penalty of death unless I ask them to or it drops on my face (which has thankfully never happened).
Quite often folk'll just grab the bar without you asking and assist the last couple of inches for no reason at all. I've had a guy who tapped the bar at the top of each rep for some reason.
Then there's the arseholes who try and only use one hand. Like you're going to be able to one-handed reverse curl this bar off of me, idiot.
Oh god and those dicks who lift it like a zercher squat. What the fuck is that all about?
I hate spotters. Thankfully I rarely ever need them.