I also have few friends. I think this is the main reason why:
(Probably the same for a lot of us here)
-
90% or more of people are less intelligent (This is true if you have an IQ of 130 or more) and
getting along with people of dissimilar intelligence (even if it is only 5-10 IQ points) can be difficult.
If you have an IQ of the average 100 there's going to be a
lot more people in the suitable intelligence range to get along with than if you have an IQ around 130 or more.
Interestingly both my best friend and I scored the same exact intelligence,
and my parents who've been happily married for 27 years also scored the same exact intelligence.
So I definitely think it's important to have a similar IQ to have a good relationship. If two friends don't have the same IQ the less intelligent one will feel intimidated all the time and the more intelligent one will be annoyed by the other's lack of intelligence all the time.
On a random note I've always felt like I've gotten along with more people in Japan. I feel like there's just a larger number of intelligent people there, and sure enough looking at some statistics recently the average IQ there is 107, versus the United State's 98.