My first trip to work on a new bike my rear wheel collapsed. 9.5 miles into my 16.5 mile commute, 5:00 AM. I decided I would rather get stranded at home than at work, so I turned around and started limping home with the tire all wobbly and lightly rubbing against the frame and fender. Three miles from home I encounter my only significant hill climb and I decided to walk. At the (almost) crest, I decided to ride it out. Tire started rubbing pretty heavy and was a chore to pedal. The last two miles are (effectively) down hill, so I was able to nurse it home. The last 1/4 mile saw the rear tire pretty much fully involved with the left frame rail and I could smell the tire. But, being so close to home my mechanical sympathy was long gone. Chugged the last few blocks and parked it.

Changed out of my soaking wet riding clothes (oh, and it was raining) and into work clothes and motorcycle gear and sped off to work. Only 45 minutes later than usual.

Lesson learned: After rebuilding a wheel for the first time, give it a solid test ride and keep tuning until it's tight and right.