I haven't had a bad experience and hope not to ever have one. 

Keeping in mind that there are so many differences socially, economically, culturally, etc., every client is different, with differing needs. If you're really good with people, you change to fit their needs, no matter how 'difficult' they may seem. Be empathetic and ask leading questions, this makes a person open up a little bit more. 

I know that there are people out there looking for a 'deal', but if you prove your worth and go the extra mile, the client will appreciate you even more in the end.