I define many acts I do by their pointlessness. The more silly and pointless an activity, the more likely I will find some joy in it. My main hobbies are running and biking, which are nearly perfectly defined by going in a circle to end up where you started. I make these even more silly with a desire to go over a certain bridge or reach a milestone only to be forgotten later. Doing something for the sake of doing it is probably the best reason to do anything. When Werner Herzog hauled a steamboat over a mountain, nobody but him probably really believed it was necessary for the success of the movie, but here we are.
Biking seems to be the best reason to do things pointlessly. The first time I did Prof. Dave's race, I learned that his manifest does not necessarily need to be strictly followed. He believes it is the most direct route, but other less steep routes could be better. When faced with going directly over a hill compared with skirting around it, another racer and I decided we had to go directly over the hill "in the spirit of the race" (and certainly not because of any mind altering substances that were kicking in).
Similarly, going to the highest point in a city to celebrate the legalization of cannabis is a pretty silly thing to do; however, on a bicycle, it is no small feat. Cycling endlessly up hills on the west side of town to reach an outlook is a pretty nice experience, regardless of if there is a good reason.
Perhaps the Bob Ross quote that remained on my fridge is a key part of my philosophy: "This is your world right here, and there's no right or wrong. As long as it makes you happy and it doesn't hurt anybody else, then it's fantastic." Biking up pointless hills, running at absurd hours of the morning just for myself, keeping a blog that nobody reads or knows about, playing new songs on the piano with my headphones in, these are the things that make life worth living, and they benefit almost nobody except for me. Seems kind of selfish, but I don't think it's hurting anybody.