At regular Somchai hole in the wall kind of joints, complaining, even discreetly, is about as useless as teats on a bull. Their sensitive fragile little egos can't handle it and there's about a 70% chance of getting unwanted DNA in a re-done dish (on the off chance they even give a flart) . That and their main tool of the trade is a meat cleaver 555.
At classier joints/hotels, especially places with Western style management/training like Wine Connection for example, no problem provided it's a legit issue and not some woke retarded weirdo feeling offended that his seared LGBTQ rainbow trout doesn't come with an instruction booklet on how to ask its gender identity.