I just did the stupidest thing ever

Paying for a pomegranate raspberry green tea at Café Pi, I ready a five-dollar bill just in case it costs more than I could buy with my two dollar coins in my pocket. The total comes to $1.50, which means that I could give the man my two dollars with a fifty-cent tip and conserve my five dollar bill. Instead, when I reach into my pocket to fish out the two coins, I find them stuck amongst my camera, phone, pen, and keys that also occupy space in the pocket. Panicking, I just hand the man the bill instead. However, upon receiving my change, I am still working under the plan that I will give what money remains to the man and I dump my precious $3.50 into the tip jar. I realised my mistake right away, but the jar is such that one cannot remove any money without using one finger to fish it out and it is impossible to do so without looking like a big asshole or a thief. So I walk away, having payed more than triple for something that's just okay, something I ordered just so it wouldn't seem like I was just stealing the café's internet. It's not being a good person if you didn't want to do it and if you don't exactly have the means. Of course, there are some who think otherwise, the scum.