Why does he keeps leaving me on seen?

So I was talking to this guy in my class, I would catch him looking at me and secretly smiles whenever my teachers pick on me on class but I tried texting him FIRST (something I've never done) he sounded pretty nice but he left me on seen but messaged me later when school ended then we talked for awhile again and left me on seen again. Like, I would see him looking at me while he's talking to his friends or talk to me in class like for example, I turned around to ask my friends something then he'd jump in and tell me the answer. And Iast Friday was my first day training waterpolo, I admit, it was super tiring because we had to swim 400m before we actually started playing waterpolo and I saw him laughing at me like in the "i told you" face (I'll show you our conversation at the end, i admit, i sound super annoying but I'm just super nervous.) And when we had to switch positions, our coach asked us who would like to guard me and he was like, "me, i'll do it" and i was like "uhh ok" because we had to like jump over each other and shit but yeah I don't know maybe he just does like me i guess? thats why he doesn't wanna talk to me
Why does he keeps leaving me on seen?
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