Yes, Wishful Thinker, I relate to this so much. Particularly the hair salon. I would be the same way.
Hairdresser: *gives awful haircut*
Me: "Thank you, it looks great!"
Lol
I actually saw a meme of this exact same thing. I think other people struggle with the hair salon too. There used to be a humor page called "awkward conversations with the hairdresser."
But I'm very sorry you had that experience. Being drenched in a cold shower should not be part of a hair salon experience! And our hair is important. It does matter to us.
Yes I can relate to not wanting to "rock the boat." And for me it comes from my past and ppl close to me like mt mother as well.
I don't think you should be so hard on yourself, Wishful Thinker. A lot of people struggle with confrontation. If it really bothers you a lot though, consider taking steps to be more assertive in your communications. The Assertiveness Workbook is a good book (don't know who the author is) if you're looking to learn through a book.