Every year on my birthday, I treat myself to an unreasonable purchase. Something that I always wanted but wouldn't just buy it normally because it wouldn't be practical or reasonable. Something like an expensive toy, or a fun gadget, or a hobby kit.
This year I'm indecisive between the Steam Deck and the Meta Quest 3. You might ask why would that be unreasonable. Because I have a family with a newborn now so I don't have much free time to game anymore. It would be a waste because I can only play like once or twice per week.
I would love to hear about your desire for an "unreasonable purchase" (within your budget).
Honestly probably just some very fine food with my direct family. 3 course dinner with some nice cocktails. I do have hobby related expenses but I dont consider them something special.