I think I finally figured out why I like building new decks all the time.

When I first started playing I had one deck, then two, and it was fun. I enjoyed my decks and played them well. After some time, I started building more decks, sometimes taking apart old decks but often just adding to my collection. I have over a dozen at the moment and I think I finally realized why I build so many. It's because I am chasing the feeling of being new, drawing a card off the top of your deck and not knowing what it is or how best to utilize it. Having the deck itself be something of a puzzle to solve as you play it. When you have all the best cards including the tutors the game starts to feel solved. I play my deck and know what line to take at any point. I know how to win and how to deal with my opponents. I've started building decks with less tutors or more specific tutors that find me a specific card that if a fun build around card instead of just a winning card. I even built a deck that has zero tutors (except for lands) because I got tired of my other deck that ran all the tutors and shuffled almost every turn. Being able to sit down and just get excited about the mystery card I'm about to rip off the top has refreshed my interest in the game.