the lack of other fishes.

You and me.
Meant to be.
Immutable.
Impossible.

-Stand Inside Your Love by The Smashing Pumpkins

Impossible, the key word in most cases. Or at least most of mine.
Ever notice that no matter how many people tell you the cliche line "there's more fish in the sea", it doesn't make you feel any better, much less acknowledge that? When you have feelings for someone, you have feelings for that person. It doesn't matter how many cute people they throw at you, nor does it matter who did what.
You seem to want that person, and only that person. If you can't have them; you won't even feel half special, no matter how many nice comments other people throw at you. Your image only matters to that one person, at least for now. Notice the fact you barely ever get a chance with that special person.

Then, the case progresses. You continue to have feelings for the same person, only now they seem to be increasing in intensity (forgive the predictability). Unfortunately, you don't want to tell them. "What will they say?" "We are good friends, it'll get weird!" "No, I don't think I can." "I'm too shy." "They'll never like me back, what's the point?" "It'll just feed his/her ego."
Excuses, excuses, excuses. Sometimes it's all you ever seem to do, make excuses for things. This is most likely because you're so worried about what others will think--especially that special person. Of course you can't tell them, you like them too much to even let them know, ironically.

Maybe you're scared of what they'll think, maybe you're scared that things will get weird. Or maybe you think you might look stupid, or will feel embarrassed. Seems to me like you don't want to tell them just because you're finally admitting we have a crush on them. It's a kind of closure that you aren't ready for yet. You're putting it out in the open, and actually acknowledging the fact. You're telling them you like them, so of course that means that you do, and it might not stop anytime soon. You can't deny it much longer. You've told them how we feel, and there is no turning back now. Occasionally, and I mean on fairly rare occasions, they feel the same. It's a "wow, I was about to tell you the same" type thing, which sometimes happens for people in good situations. And notice that by sometimes, you basically mean never.

More often, it's "sorry...I don't feel the same", "oh" or "I'm sorry, I just think of us as friends". What then? You've poured our heart out, only to realize that they don't feel the same, and now things have a fair chance of becoming awkward. It hurts to know that you do in fact actually have a crush on this person, and you've used up your last bit of courage (and chances not to mention), on telling them how you feel.
They are going to walk back down the street you just walked up together, and they are going to get back on their bus that sends them to their part of town. The streetlights are going to shine dully down on the black pavement where yesterday's rain still lingers. You accidentally step in a puddle but continue on towards your destination. Maybe home, maybe not. Maybe anywhere...You'll walk the opposite way, feeling slightly better, but still so empty. They really don't feel the same, despite everything you tried to tell them. No chance, just as you suspected in the beginning, before the hope got to be more than you could bear.

Climb into your car, drive home, and proceed to play sad music on repeat while you finish yesterday's ice cream. Then crawl into bed, play the day over 10 times in your head, and shut off your lights because you're on the verge of a drug induced sleep. But despite the drugs that are working to put you there, you probably won't sleep that much anyway. Thoughts are going to run through your head until the point of exhaustion.

When you wake up in the morning, you're going to vent to your friends, maybe they'll help you, and maybe they won't. Chances are, they're going to tell you that there are "other fish in the sea". Like it even matters to you now. The only fish you wanted has just slipped off your line and is swimming quickly away, as your boat drifts away into nowhere. Notice that these are the same friends whom you told that they'd always have a chance, that they could always do something. But of course you can't follow your own advice and it sure isn't going to help you now.

All that's left to do is wait. Wait until you start lusting over the next person. Only time will tell when this happens, but of course you're going to be scared while you wait. Sitting alone and wondering, who is going to be the one to crush your spirit....this time.