I Told My Regular Patrons Their Secrets Were Safe With Me, But I Swiped Some Notes For My Own Fun

So there's this guy named John who comes in every Thursday night. He always orders the same thing, a double espresso and a shot of whiskey, and he likes to sit by the window so he can people-watch while he drinks his coffee. One night, about two weeks ago, I noticed him scribbling something down on a cocktail napkin. As it turns out, John was jotting down all these deep thoughts about his ex-girlfriend, how much he misses her and how he still hasn't been able to let go despite her clear disinterest in getting back together. I've always told my regulars that I'm their friend here at the bar, that they can trust me with anything. Of course, it's all part of the job, to build rapport, make them feel comfortable so they keep coming back and spending money. But this time was different. When John had put his pen down and seemed satisfied with what he'd written, I thought to myself, 'Why not have a little fun?' So, as casually as possible, I snatched the napkin from him when he wasn't looking. It's been folded neatly in my pocket since then. Now, it's not like I've gone snooping through John’s personal life or anything, I just read that one note. And it got me thinking: What if I started taking notes on everyone here? Their daily drama, their deep, dark secrets they don't even know are written down and stashed away in a small notebook under the counter at work. Could it be that my bar is a place for not only drinks but also for capturing moments of truth? But then again, I'm starting to worry about crossing lines here, should this be just another routine part of being a bartender? Or is there something more questionable going on? What would you guys do if you were in my shoes? Am I the asshole here?