Sometimes, the other organist at our church plays with her left shoe off but generally, she keeps them on. I played without my left shoe only once, but the reason happened to be that I was wearing these really big boots and they were hitting more than one pedal at once and it was really annoying, so one sunday, i just could not do it. I've never done it since then. I just don't see it as comfortable. I see it as feeling wierd to my feet. Even wierder, my church has a B3, so while the church watches you playing the organ without shoes...anyway, if you feel comfortable with no shoes, don't wear shoes. But people come to church and take their shoes off, so does it matter if you're on the organ?