Why my crush is acting so CHILDISH?

My crush is most sensible and mature person. But whenever we meet at collage, in case if I forget to greet him or dont pay attention to him, he would make face at me, roam around me just to show I forget to pay him attention. However if I greet him, he would b happy for whole day, escort me to my class, help me with notes and take care of me. Why is he so immature? He does that only with me
Why my crush is acting so CHILDISH?
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