Why do you think is the most common reason for people to be incel?

This may be impossible without a proper survey of incels. But sometimes I feel the reason we're incel is because of certain common factors. Lack of friends since childhood is one of the commonest. Why are we the kind if people who are unfriendly and are lonely since our childhood? I know we're not unfriendly or anything, but we tend to end up that way.