I once turned one down because in the middle of my interview the owner of the company took a telephone call from his wife.
He was so nasty, loud, and condescending to her, I decided immediately that I would not work for this guy for all the tea in China.
I once turned down a job because the vending machines in the employee lunch room were so overpriced I had to ask myself “Why is this company looking at their employees as a source of revenue rather than a source of profits?”