I like the middle of the week a lot. The thing is I always look forward to sessions a lot and want them to hurry up and come so it makes sense not to have it on Monday, JMO. Because then all you really have to look forward to is a long work week.
Re: sessions at the end of the day.... I used to worry very much about planning therapy and then going out to be with people afterwards-- like somehow it would rub off on the general mood, or I would be a downer to them. But it doesn't seem to make much of a difference!