Meeting someone you like, who is single, who you have great chemistry with, learning that they are not as into you as you are into them. Therefore, you need to unlike them.
Meeting someone who you spent a great deal of time and started developing chemistry with, learning they have a girlfriend. You know you are too good to steal anyone away from their partner. You know, for that moment, you are that stand in girl friend. You can feel he misses her. But you also feel that he likes you, because you are smart, and complements him in different ways. But you don't want to get hurt. You don't want someone else to get hurt because of you. So you need to unlike someone.
Meeting someone who is nice and patient with you who knows something you don't. Who looks at you with those eyes, like someone who appreciates a girl who's strong with a good head on her shoulder who pushes herself as hard as he does and still enjoys a good beer and an inappropriate joke at the end of a long day. Who gives you an unexpected big hug after the big project is over. But he's legally not available. So you need to unlike someone.
So you keep your distance, and you try to keep those memories as something precious of your own. Then you leave and move away, knowing you will never see this person again.
And you hope, secretly, that one day, you will meet that someone, who wants to create new memories with you. Who isn't for whatever reason, unavailable emotionally or legally. Because he knows if he doesn't say something, the moment just passes you by.
Someone who wants to make plans with you.