That's such a tough question to answer! There are soooo many panels that were a challenge, I think I draw something like that almost every other page. But I guess this one would be the hardest, at least of the recent pages.
Not so much because of the perspective, but because being someone who doesn't drink I don't have a whole lot of experience with what a bar looks like. I had to observe the shit out of tons of bar pics, and I still wasn't totally sure what goes into the layout of one as far as what's tools are mandatory, and how the placement works. It was also tough with the bar patrons since I was drawing other creator's super stylized character in my style.