I avoid adding '.' to my path because I work on a lot of different linux and unix systems as part of my job, and having a consistent command line I can use without having to remember where I am and how I set things up is more productive for me than saving a bit of time on my personal system.
For the same reason I don't use a custom .vimrc file; it's great when on a configured system but causes problems elsewhere.
For years I held a similar philosophy, then I decided, "Screw it, I can just copy .vimrc and .bashrc to whatever system I need, and if that's not possible, I can adapt to the defaults." I haven't done too much customization yet, but after seeing some example .vimrc and .bashrc files online, there's a lot of potential for improving productivity.
For the same reason I don't use a custom .vimrc file; it's great when on a configured system but causes problems elsewhere.