As any professional user I tend to work a lot with paths. But one thing that drives me crazy is that fact, that when I have both a path and a layer active and use Free Transform the path has priority and gains focus. In some cases that probably makes sense, but I would love the ability to lock paths like you could do with layers. That would also enable us to use paths as guides. There have been numerous feature request on angled or arbitrary guides (like in Illustrator) and I would love them too, but theoretically you could at least use paths as guides. But right now that's a pain because as I said as soon as you hit CMD+T (for Free Transform) you are not working on the layer anymore, you're transforming the path (hence you transform your guide).