When a girl asks to see me, or tries to sit with me in class, or tries to make chit chat with me on campus I normally oblige.

However, I am currently in what I call 'cocoon mode' where I am focusing on working out, my job, personal projects, and general self improvement for a while because I am going overseas for 6 months soon.

I have noticed that after bumping into these girls again after acting uninterested and not being super outgoing or talkative with them they seem to be pissed or holding a grudge against me. Why?