After a great rest, it's natural to not want to immediately go out of your way to make the bed look pretty.
The most common excuse is "I'm just going to be in it again tonight."
It's not about the bed looking nice, though.
It's about the routine. It's about sticking with a regimen that works.
When you don't make your bed when you know you should, you aren't following your own rules. You're letting yourself down without even knowing it.
This type of inaction is akin to landing a large client, receiving the first check, and overlooking the fact that you have a lot of work to do to make the project a success.