I have no problem making friends, but I have much more trouble making close friends and maintaining that sort of relationship.
In my first year of Uni I tried very hard to talk to lots of people on msn and in person about potential common topics. But when I switched Uni courses the year after, I gradually drifted apart from them as it became very difficult for me to maintain contact with 20 or so people, let along the 100+ friends and acquaintances I've met in Med.
Because of my difficulty in making and maintaining close friends, I don't bother talking to people anymore unless I happen to bump into them. Then I'll try to be friendly. My friendships with most of the people in my current Med course are superficial and I have no friendship group/clique, but I'm not upset or envious either. I have my own personal things/goals to attend to, and I find it stressful/tiring whenever I have to talk to somebody, even if it's small talk.
A bit sad, but I'm trying to focus on myself and my own ambitions now, and less on others. I know these close friends don't last. But nowadays I get enough enjoyment from social chit-chat, if the exchange/discourse happens to be successful.