Everything I've ever been passionate about, has been something I've done a lot of. I've always thought that I've done a lot of something because I liked it, but it turns out it's more the other way around.
Sure, there's the initial spark, the excitement. The "new shinny thing" aspect to everything, but that wears off, and then what do you do? You keep doing the thing and it's only when you get semi good at it that you really like it.
For years I had a guitar and I didn't like playing it, so I didn't. I wasn't good at music, I didn't have a "good ear" I took lessons- they didn't help. It wasn't until I had had a guitar for 7 years that I actually started playing it, and in the beginning I didn't like playing it at all. My fingers hurt, I sounded awful, no one wanted to hear me play. In fact I don't know why I kept trying to play at all, except for that I didn't have much else to do that particular summer.
After a few months though, things shifted. I got a little better, I could play chords and basic rhythms. I wrote short songs and sang along. Eventually I had "mastered" the basics, and "found" a passion.
When I worked at the bike shop-it wasn't fun till I was good at it. When I worked at Daves it wasn't fun until I was the old know-it-all. It's simple, things are more fun once you master them, the flow state comes easier, the challenges become greater.
I guess I was thinking I'd have that initial spark feeling with something (job, hobbie, relationship) and it'd be so good that the initial spark or discovery feeling would never wear off. Turns out that that's not how passion works. (Or life for that matter. Initial sparks always wear off). Passion isn't the initial spark phase lasting forever, it's what comes after you've mastered something and can sit down and play like an old pro.