Twice.

The first time was when I broke a chain. This was in (my) pre-cell phone days. I walked three miles before I found someone with a phone I could use to call my wife to come rescue me. It was around 0 degrees. I dress pretty light when I'm riding because I generate heat. I discovered walking doesn't generate the same amount of heat. Brrrr. I had been resistant towards getting a cell phone up to this point, but this was actually the incident that my wife finally used to make me get one.

The second time wasn't too long after the first. I had two consecutive flats caused by a complete tube blowout. Fixed the first blowout, but I only had 1 spare tube with me so after the 2nd tube exploded (rather impressively, I might add) I was done. Both tubes were damaged to the point where they couldn't be patched. Called my wife to come bring me home. Turns out I had a split in the sidewall of that tire which was causing the issue.

Did the walk of shame an additional time where I had a flat less than a mile from home and I decided it was close enough to just walk the bike home and use my repair stand to fix the tire rather than try and do it on the side of the road.