a friend to all is a friend to none,

I think that a lot of people are thinking about this proverb in the wrong way. A friend to all is not synonymous with being self-serving or taking advantage of others, but rather it means you have friends on both sides and can help them out when they need it. I do not think that people should stop being friends with their old friends because they have new ones. I am perfectly fine to help my old friend out but if they continue asking for favors without reciprocating, then it is time to show them the door and cut ties with them. That said, there can be a downside of trying too hard to maintain friendships regardless of who you are friends with or what type of friendship it is. Sometimes when someone gets close enough to know all your secrets, like an ex-girlfriend or mother’s best friend’s son in this case, things go sour quickly and before you know it everyone involved has turned on each other. This may seem unnecessarily dramatic sometimes but at least we were