My granddaughters and I had some bad haircuts a few years ago. The girls cut bangs that were a big pain to them and I went to a new stylist who did not understand my poker straight fine hair. He was more interested in showing me how skilled he was at cutting (a lot). We recovered, but it is a painful and lengthy process.
I have found that bad haircuts happen when you are trying to something that is counter to what your hair can do (think eighties perms) or that you have unrealistic expectations.