Just to balance things, I just returned (literally an hour ago) from SF, having flown in to SF for a week, then to Seattle and back to SF before flying back to the UK, and the TSA were all very welcoming, greeted me and made conversations, jokes and all engaged in a very pleasant manner. I was very impressed!
In SF, I believe they are private screeners. In SEA, they are unbelievably friendly and professional. Same goes for customs enforcement btw. Plus there is nothing to make you feel safe than having security that is obviously more competent than average, however low a bar that may be!
