Wait, you only just did that for the first time this morning? That's actually wild to me. My mom was a total drill sergeant about it, so I've been making mine since I was like, five. Feels weirdly official now, like the day can actually start.
My older sister used to bribe me with candy to make her bed when we were kids. Reading what @dakotajones said about it framing the day is spot on, because now if my bed's a mess, I just leave my clothes on the floor too. It's a weird domino effect for sure.