Hand signs?

Today I was commuting to another town and back, going through some rural areas. On my way there, a truck threw up a hand at me as we passed each other. I thought maybe he was blocking the sun since what he did almost just looked like this hand emoji ✋. But then on my way back, another truck did the same thing! Maybe he had his thumb down? I’m not sure, he wasn’t flipping me off or giving me a thumbs down.. but it was definitely towards me.. even if it just looked like a hand thrown up for a high five that was left hanging. Anyways.. just wondering if anyone has experienced this / has any insight