What’s something that made you believe that a friend was rich when staying at their house when you were younger?

The fact that he had a maid who answered the door when I very first went to his house. And then he told me his dad is a doctor, so that explains why when I saw more of his house, that I noticed his house is huge and has multiple staircases that go upstairs, a cabana with a pool next to it, a backyard with a big ping pong table, and a basement that is a hang out room, bar area, and gym all in one. Yeah, very fancy.