When I started shaving with a straight in 1980, I was totally self-taught and used my right hand only. It never occurred to me to try and shave with my left hand. One of the nice things about a forum like this is that you are exposed to new ideas. Typically, I resist them but some ideas keep gnawing at me. I have made several inconclusive attempts to use both hands and have recently made a lot of progress. It is now more natural for me to shave with opposite hands, left side of the face with the right hand, right side with the left but not 100% symmetrically, i.e., I still do more with my right, such as the "center of my face", mustache chin and center of the neck. I estimate that the "weirdness" goes away after about 10 shaves.