Has a guy/girl you liked been interested in your friend instead?

I think this happens to everyone at some point. You move on, really. You must know that your friend has great qualities, or they probably wouldn’t be your friend. Apparently this person sees something good in your friend as well.

There are a couple things:

(1) there really isn’t a problem for you to deal with that involves your friend unless your friend and this person start dating. Then it’s just the same (or you should think of it just the same) as the person simply not being into you.

(2) you should not say anything to your friend about your feelings to the person, in my opinion, before they start dating/it seems like it’s not really going to happen. You do not want to create a situation where you feel betrayed because they start going out, or where the friend ends up blaming you if they decide not to date the person.

(3) if they start dating, wait until it’s serious to say anything if possible.

I don’t recall that, but I do remember being the friend. And it didn’t turn out well for any of us.

Yes, one friend who was interested back, so I faded away from them both (and also because we were teens, and you know how kids are when they start new relationships with their “our relationship is a special snowflake!”-y behaviour), and one friend who wasn’t interested back, so the guy faded away from our group.

No. Actually I usually find myself on the recieving end of this where I’m the one the girl likes (even when I show no interest).

Yes, it has happened. I think it’s something everyone goes through at some point.
It’s hard to separate all of the feelings going on in that situation. I remember feeling betrayed by my friend if she entertained his flirtation towards her, which in turn put her in an ultimatum-type situation (very unfair)
This caused problems in our friendship re trust, etc.
We were young. I’ve learned a couple of things from that:
Accept things as they are. Take on board what @theonlyneffie said and also, learn what level of friendship I have with different friends.

I was used to it ,I have hot friends, or used to.
I was not as social as my friends were so they got all the attention till I broke out of my shell.
Eventually I found someone who liked the quiet one.

Yes, the girl I had a crush on was more interested in my best friend, her husband, than she was iin me. Despite the considerable pile of cash I offered her to do me, she turned out to be a selfish bitch. She claimed that she couldn’t “betray” her husband. I’m sure he’d never object to my having fun with his wife—what kind of friend would he be otherwise?

Yes, and it was a painful summer. I worked at a camp for a couple of summers, and during the second one, I formed a crush on one of the boys there. During the next summer, he started seeing my good friend and roommate. She worked in a different area of the complex while he and I worked in the same one. It was agonizing, as I cared for them both. I just kept my feelings to myself, as they were very happy, and there was nothing I could do to change the way he felt about her.

Years later, I met the guy again, along with his wife and their son. She is a very lovely lady, and I was able to feel sincere happiness for them. I’ve recently tracked down the roommate on Facebook, and it feels like old times being back in touch with her. Maybe one day, I will tell her why I was distant and morose that summer.

I saw it in action,m and it made me sick.

Sure – it’s natural. No worries.

Yup. It feels bad at first but I restrain myself from liking him even more, by keeping myself busy, etc. But I suggest not to avoid them – it’ll be even more awkward if your friend found out that you like him/her too, especially if he/she is your good/best friend.. It certainly is hard to look at someone that you like liking another person. But you’ll get over it eventually, trust me :) Just keep yourself busy.