One provider I saw had an emotional breakdown earlier in the week and was crying on the phone, but she ended by saying she was looking forward to our session because she felt it would make her feel better. It was a fantastic session and very intense. Sad to say she got out of the business within a few months.
Similar thing can happen with clients if they receive bad news even a day or two before a session. The mood is just not there. I was fortunate that a provider was more like a friend once and we had dinner while I discussed a life change I was going through. Made the decision much easier.