It's usually not me, it's the bike. A bad ride is when the innertube explodes because the rim has been worn down enough by the brake pads that it cracks and bends, allowing the bead to pop loose. You then have no choice but to wait for the next bus (assuming your town has buses with bike racks on them), or to just ride home on a damaged rim and flat tire. Or when you puncture three times and you've only carried two spare tubes. Twice I've had the frame break during a ride, or the chain break. And another couple of times I've had the freewheel threads on the rear hub come separated from the rest of the hub (fixed gear). You learn to be pretty resourceful as a cyclist. Sometimes you just have to figure out if you can fix things enough to keep riding.

Luis