When I met my future wife I was 21, and she wanted me to grow a beard, so I did.  Since then I have occasionally asked coworkers who have complained about shaving why *they* don't grow beards: the most common answer is "My wife doesn't want me to." 
Moved to COFF ... while bearded UNIX folks do seem to be a common thread, I think we are stretching Warren's patience a tad.   So ... I have sort of a different story. 

I had shaved in off and on during college and in the first few years I was working but had grown it back before grad school.  I still was not sure I liked having it, and as I got close to finishing, I mentioned to my officemates at UCB that I'd shave it when Newton (our advisor) signed my thesis as a signal to everyone I was done.

So the day I came into the office clean-shaven, Peter Moore looks up and remarked, 'now I know why you wore one.'

So, I showed up at Masscomp without it and was quickly ostracized as so many of the SW team had some sort of facial hair, I quickly grew it back.

Roll forward 20ish years and my wife egged me into shaving it off one summer weekend.   Our then 5-year-old daughter cried -- she wanted her Daddy back.   I've had it ever since.

That said, 20 years later she and her mother both claim I would look younger if I shaved it.  But at this point, I kinda like not having to shave my neck and lower chin every day if I don't want to; so I have ignored them.