Wasn't an argument as much as general irritation about some instabuddies.
I've taken the role as leader on a few dives with people I haven't dove with before and I've found that most of the time they'll stay behind me, even if we talk about swimming side by side before the dive they'll just trail off to slightly behind me.
I'll give them the sign to move up and to swim alongside me but more often than not they either don't understand it or they just don't care, so I'll have to keep eyes in the back of my head to make sure that the diver who doesn't even understand basic signals stays in range.
Grinds my gears a bit, and I'll typically talk with them afterwards and they'll be like "Oh, so that's what you meant when you were making signs and stuff, I had no idea"...