I think people who are overly self-conscious about looks and always think 'Man, I'm ugly!' will have a harder time making friends than someone who gives it not much thought and simply acts like they would.
Some of the funniest friendliest people I know could be considered unnattractive due to being a bit on the heavy side, but that doesn't stop them from making friends like no other. Being just attractive wouldn't get you many friends if you were either terribly shy or unsociable.
It may be true that you would be approached less in some circumstances, but how many friends are usually made by hand picking someone and walking up to them saying "Heyup, let's be friends." Isn't is more due to inevitable circumstances that you make friends? Like being put into groups during some activity, sitting at the same table in schools/college/university or getting to talk to one another in a similar situation of some such (at work/neighbours/etc). This usually leads to people talking to one another and getting to know one another better.
Regarding jobs though, attractiveness may hold the edge in getting a job as it's less about having a nice personality and more about being able to sucker the employee into believing that you're hard working. This would probably be easier achieved when having a pretty face to look at while you're telling them that you're 'greatest weakness' is that you 'work too hard'.
