I’m not a very social person. I try to be nice to people, but overall, I have a very small group of friends. It’s hard to maintain a large number of friends and give them all the attention they deserve.
The same applies to your cast of characters in a work of fiction. Keep them under control. It may seem like a lot of fun to sit and make up characters, but in the end, you risk losing the focus of your story and confusing your reader.
There is a story about The Stand that I came across in which Stephen King realized his cast of characters had gotten out of hand. His solution was to immediately kill several off. This resulted in the closet bomb scene that you may remember, if you are a fan of the book.