This is a tough one because good friends are hard to come by. So, the question is, how do you know if someone is a good friend?
I have these 2 friends. We are all 3 friends. We have been for 20+ years. One of them I met in high school. We were attached at the hip until he went off to the air force when we were 18. But, we still kept in touch, he was my best man in my wedding, the god father to 2 of my kids. I hardly ever see him anymore though. He lives 45 minutes away, has a job, 2 kids, is in the Air Force reserves which takes one of his weekends each month, his mother died last year of cancer after a 2 year fight. So, I know he has a lot going on. Now that she has passed he is trying to spend more time with his dad who hasn't gotten over losing his best friend.
The 2nd one, I met through the first one. Now I am better friends with him than the first one. We just have more in common. But, I even don't see him all the much. He works ALOT. We both have 4 kids (ages 2-10). They are all either in school and activities or very close to it.
Here's the thing though. Will that friend be there when you need them? In am going to be getting divorced (long story). Friend #2 is the only one who knows. He now makes it a point to check in on me frequently. When I have had my bad days, I call him and he drops what he's doing to listen to me and help me. I also know when I do finally tell friend #1 he will be there in his own way too. (His wife is a HUGE gossip, that's the reason he doesn't know. Because once SHE finds out, the whole world will know)
If you ask yourself the question, "Can I count on him/her in an emergency?" and the answer is NO, then you know its not real friendship. If the answer is YES, then you have to not take things so personally and accept him/her for who they are.