The last time I complained at a restaurant was when I found half a ladybug in my salad at Ruby Tuesday’s. And it wasn’t complaining so much as just whispering it to the manager so he could be more diligent with the washing. I actually went back up to the salad bar and found the other half so other customers wouldn’t flip out. He was more than happy to comp our salads and drinks (party of nine, good deal for us)
I often ask for dressing on the side, or ask to have something left off. That’s not extra work for anyone, so I don’t consider it high maintenance, but I do tip extra if they get my special requests right.