Two come to mind;
First in the 90's - I was in a pretty successful original band. Got paid well enough that we could pay roadies. At a lot of the shows there would be some guy giving me the finger standing there behind his date who is enjoying the show dancing her butt off. They were probably pissed that their girl was paying more attention to me/the band than them. One night my 6'5" roadie was standing next to my side of the stage. I nodded at him to come over and I told him some a**hole was giving me crap. He eagerly starts into the crowd. At every guy he would mouth "is this him?" I'd shake my head no. After about three attempts with three different guys, the middle finger guy sees that I'm sending my guy after him and he tries to retreat. I lock eyes with him, mouth "that's him!" to my roadie. My roadie sees him, rushes to grab him and drags him out of the club. The kicker - his girl didn't stop dancing and didn't even notice her guy was gone! lol
Second was last month. 80s tribute band, playing in a place with no stage. I hate places with no stages. There's no barrier between you and the drunken fools. If I want to interact, I'll come down to you. Now I am a pretty easy going guy unless someone keeps doing something even after I ask them not to several times.
I have a teleprompter box that I made, looks like a monitor. Has a solid screen around it like a sun screen on a tv camera. Anyway, this drunk guy is dancing in front of me and he starts putting his foot on top of my teleprompter sun screen. I get his attention, shake my head no, while telling him - no, do not put your foot on that. He takes it down. A minute later, does it again, tell him no again, takes it down. Third time he steps hard on the screen and pushes his foot through it breaking it. Then he purposely puts his foot on the monitor and then the singer's teleprompter. That was enough for me and I rushed him with my shoulder (still playing) and yelled that he better get out of there or I was going to rip his head off. His friends and some bystanders pulled him away and I didn't see him the rest of the gig.
Oh bonus story. Punk band, early 90s. Playing at a place with a high stage (Yay). Big crowd, I was standing in my best punk pose at the edge of the stage. This guy keeps grabbing my leg and pulling me of balance. Tell him to knock it off. I pull back. Stand at the edge of the stage again and he does it again, and then 2 more times. After the 4th time telling him to knock it off, I grabbed the neck of my bass, unslung it and cracked him on the head, down he goes. Bouncers came, picked him off the floor and threw him out. This they noticed, where were they when he was bugging me before? I still have the chip in my bass from his head. (disclaimer: I would not do this today (probably) I was much younger and angrier - lol) To be fair, I do give a lot of warnings.