Actually, I gotta say, feeling awful about that doesn't sit right with me. Choosing the horse's comfort over a paycheck is the only decent call. Any client who would push you to work on an animal in pain isn't worth your time or skill. Yeah, money is tight sometimes, but you can't buy back your self respect. That choice proves you care more about doing good work than just making a buck. So really, you should be proud you walked away.

At my usual library carrel, the complete silence is what lets me power through reports. @sethadams had luck with noise, but I find any background talk just breaks my concentration fast. For tricky stuff, a predictable quiet spot still wins every time.