Actually, I think it's similar to what keeps one's interest in a movie, TV show or novel. A good story writer will have the characters experience a challenge, set back or other difficult situation fairly regularly, which keeps the audience wondering how this latest challenge will be resolved.
It's the whole cliff-hanger concept. The hero or heroine is trapped in a dire circumstance as the episode ends. This open issue, this unanswered question is what keeps them coming back to the next episode with interest and enthusiasm.
So what about shaving?
From personal experience, when I had reduced my daily shave to the simple methodology of one razor (the Merkur 33C), whatever blade was up in the rotation, and one of my three shaving soaps, the outcome was certain, there was no challenge -- no unanswered question, and, as a result, the process became (yawn) a bore.
However, when I reintroduced a variety of razors -- many of which brought a bit higher level of risk and reward -- the challenge was back. With that came the daily question: how well will today's shave turn out?
That question brought anticipation and enthusiasm. It was that unanswered question that could only be addressed with, well, let's find out. That small question brought all the fun back just like at the beginning.
Happy shaving in the new year!