To me, a good friend is someone you can rely on when you're in need, but it doesn't mean that you have to see him/her regularly. In fact, we usually see relatives or acquaintances more often than friends. On the other hand, although I have been told that I shouldn't befriend people at work, some of my friends have been workmates previously. That's probably because as we come from similar backgrounds, there will be more possibilities for both of us to understand each other.
My favourite quote about friendship is "A real friend is someone who walks in when the rest of the world walks out".
I think that having too many friends is impossible beccause we, as friends, work differently. In my opinion, there are givers, takers and sharers and handling with friends is not that easy- especially when dealing with emotions. Some days we may feel at ease just with acquaintances, and some others we really need a warm hug, so that a friend will make it after a whatsapp message.
I have a tendency to have better friendships with men than with women because they are not so competitive as far as beauty, occupation or family success are concerned. They're more easy-going and relaxed. And they don't necessarily talk about sport over and over again all the time!