Oh my god I think photoshop has a hideous interface. It is accepted due to the massive traction it has and the number of professionals that are used to it.
It's an interface for professionals. It takes awhile to learn, but when you do, you're rewarded with quite efficient access to the tools given how much Photoshop is capable of.
And so what then? You use it because it has traction and because other professionals use it? Or because, as many professionals find, it's the most capable tool for the job at ahnd?
I'm a pretty expert Photoshop user, and I see it as similar to the command-line. It's not intuitive to a brand new user, but once you get it, it's incredibly efficient and productive. I think this is appropriate for a professional tool.