Oh, Mikhail could make a whole list of answers for that question. The other workers find him annoying (fair). They think he's a pompous asshole (also very fair). Mikhail isn't actually as good at the whole "pretending to be a normal civilian" thing as he thinks he is (not fair!).

All he does is shrug with a who knows? sort of cheerful nonchalance. "Don't feel like it!"

The workers don't like him. Well, that's fine. He doesn't like them either. Everyone's the same in that regard, and he hasn't been able to completely shake off that part of him that the Torna Pirates had instilled. He glances sidelong at Luffy without turning his head. That upbeat attitude is... actually a breath of fresh air after spending weeks with a bunch of surly shipwrights. He's actually sort of surprised that Luffy didn't snap back at the provocation. So, sure, he'll give a proper answer instead of dancing around it like he normally would.

"Why should I break my back for some jerk who's gonna reap the rewards for himself? You saw what they're charging. It's burglary!" Or piracy, he laughs to himself. "Nah, if I'm gonna do a job, I'd rather do it myself. It's better that way, anyway— less cooks in the kitchen, y'know? Or, should I say... crooks in the kitchen."

He laughs again, at his own joke, like the asshole the shipwrights had correctly deduced him to be.