Why did this guy react this way, when I gave him a compliment?

I work at a construction site and I gave a compliment to one of the contractors I sign in everyday. I had signed him in twice before and I just remembered thinking wow he’s so cute, so the next time I saw him I just nervously said “ by the way I’m not flirting but you are very handsome “ and he turned away from me and said thank you and drove off lol, I feel like he thinks bad of me, I have no interest in him really I just genuinely felt compelled to compliment him lol

Why did this guy react this way, when I gave him a compliment?
Post Opinion