Back when I first had my folding bike I made sure I had all I needed to fix a flat; 2 spare tubes, tire levers, pump, even tire boots. I was all ready!
Until I actually got a flat and discovered that the folder (Da Hon) didn't have QR on the back . . . had it on the front so I just thought it would have it on the back. No . . . 15mm nut and me with no wrench.
Phoned my wife (yes, this was in Cell-Phone era) but it took her awhile to get off work and get to where I was. Must have walked a mile, mile and half, not sure exactly. Finally hooked up, threw the Da Hon in the back of her Subaru Forester; no worries!
Then there was the time (before I was married), when I broke a chain and had to walk all the way home, about 3 miles.
Rick / OCRR