I have to ask you a question. I am having a debate with someone as to why your ex cannot be your friend. I'm having a little trouble finding the answer. I need help. So my question is... why is it that you can't be friends with your ex?

I have a few "friends" that are real flakes. I've known them for years and years, but they blow me off so easily. I've tried a lot of different tactics, but nothing seems to stop the problem. For example: This guy that I have known since I was born and I recently started college at the same place. We live three blocks away from each other. I have spent a good amount of time at his house and he has come to mine (just friends), so I know he is comfortable spending time with me. He has a tendency to text me with a basic "hey I'll be coming over tonight" or "You want to come by for dinner" and then without warning, he will no show. What's going on with this? I don't know what to do.

My (ex?) best friend and I drifted apart a few months ago because of her new boyfriend and my busy schedule. Before, we were like sisters, but now we just ignore each other. She's recently been trying to contact me, and even though I do miss her more than anything, I haven't been answering her calls. I'm not sure if I want her back in my life. There were certain things about our friendship that didn't seem right. There were things we couldn't/wouldn't tell each other. She also liked to make me feel unimportant. I know this makes it seem like we never were true friends, but we meant everything to each other. I just don't know if I should let her back in or not? Please help?