then again there's a lot going on in those first few seconds, so sometimes it's a bit hard to separate the events.

I can think of a few that the initial reception was a bit on the cool side, but as the evening wore on, things got a lot more heated.

I can think of one that started pretty good, but then found myself not enjoying the session as much as I had hoped for various reasons.

On rare occasions they will, but for the most part, I realize that sometimes people are just nervous, and that can change a person's personality/approach immensely. Someone who may come across as distant or not really "there", may just be nervous...which usually subsides within the first 20 minutes or so...although some are still nervous up until the end, but on subsequent appointments are more themselves.  

I have found that in many situations, the first impression an individual portrays (those first 5-10 minutes), will let me know if we are compatible or not...sometimes people just do not "click", for whatever reason..no matter how hard you try, there's just something there that rubs the other person the wrong way...thankfully, these situations are few and far between