Well, my work mostly involves dealing with ladies because am in the hair and beauty industry. It gets difficult when at times a client insist on a certain hair style which you know won't go well with her due to the shape of her head. Despite your advice she still insists on the same hair style. You do you best but at the end the results don't look much good on her because in the first place, the style was not meant for her head shape. At the end she ends up complaining and blaming you like indicating that you are not good enough for the job.
Or at times the client insist on certain color during her make up. You might try advice her of the best colors for her skin tone but might insist on the ones she feels are good for her. At the end the results may not be too good.
All in all, I always try my best to make sure that no matter what, my clients leave when they are satisfied. I try to always be patient with them. If they insist on a certain thing, I try and do it so that they can see what they want is not good enough and at the end they'll give me a chance to do it as I had suggested earlier.