Why would my guy friend LOOK AT ME FROM AFAR?

i know him for 2 years & he always says hi to me whether he sees me first while i'm looking down, he gets my attention to greet me...why does he just stop walking dead in his tracks & just look at me from afar for a few moments before getting my attention? like when he's walking & then spots me & stops to look & then calls out to me (says my name) & approaches me so i could see him