I've been practicing the "no" thing this last 6 months and it really does work! I've always been like you, Trans... especially to people I am paying good money to do a service!? WTF is THAT about?
Like, do you ever tell a hairdresser that just did a major butcher job, "Oh, yeah! That looks great"....pay $75 on your way out, then go home and re-do the whole dang thing?
I drove myself crazy doing that and I'm reforming my ways!
My new favorite is, "No, I'm sorry...that doesn't work for me." Try it on for size!!