What could be the reason a guy I went out once looks at me with serious face every time he sees me?

He looks me straight in my eyes and stares at me until I’m not on his line of view anymore.

We were chatting for 2 months before we went out on our first date. After our first date he said we shouldn’t date anymore because of our ”different life goals” he didn’t want to give details what exact goals didn’t align.

What could be the reason a guy I went out once looks at me with serious face every time he sees me?
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