Not sure what you would consider a functional stoner, but I feel I'm somewhat a functional stoner, but a very nervous and forgetful one. What I mean is that I function very well, however, I tend to get nervous because I feel as if everyone around me knows I'm high. I do have the tendency to forget things when I'm high, but other than that I'm pretty functional.

For example, at work. I'm sure that if I went to work high, I'd be more than capable to do my work, but I'm too nervous to get caught so I simply won't take the risk.