Shaking Hands in Singapore

On my vacation to Singapore, when i was at the beautiful Gardens By The Bay. I met a man and we were talking about the beautiful rare plants. He was telling me really cool information like there they have more than a quarter of a million plants there, and that you can see an amazing peaceful view of the Marina Bay. Then i had to go back to the hotel because it was getting late and i said goodbye and shook his hand because it was my last day there and my flight was the next day. when i was shaking his hand i was trying to look him in the eye but he was looking down. So i was thinking what was he doing? Then he looked up and saw me looking at him and not down. But he didn't get mad at me because i think he knew i was a tourist visiting there, and i didn't know better. Then he told me that "next time i come to Singapore, look at the floor because it is disrespectful if you try to look them in the eye Know i know that next time im in Singapore to not look in someone in the eye and basically bow my head at the ground.