I can fly 3 legs in a day and only talk to 4 people. FO, Dispatcher and 2 fuel guys. It is one of my favorite parts of my job. It doesn't make me an ********* just because I don't like to be surrounded be people. Flying freight definitely requires less customer service responsibilities and flying at night is a bit more laid back. Even SDF at night seems laid back.(I flew there in a turboprop, not a brown and white jet) The airspace can get pretty busy and the ramp is swarming with vehicles and people, but it never find it as annoying as flying into a class B during the day or being in a passenger terminal.
I've been flying part 135 freight for a little less than 3 years with the intention of getting into 121 freight when I can. Looking back on the situation, I now realize that flying for a regional would probably been a quicker way to get the time I'll need to get hired by a 121 freight company. At least for now I can tolerate my job.
A friend of mine seems to like working at Kalitta and I received a fairly positive impression of Polar all four times I jumpseated with them.