Once I was track standing on a lo pro, at a red light, at the head of a huge group of nodders, mamils, normal people who just had to get to work, etc.
"I'm glad I'm at the front," I thought. "Don't want these wankers getting in my way, slowing me down. I've got places to be"
I waited, poised and patient, unmoving, statue-like even, for the whole long light cycle. And when it finally went green I leapt forward, pulling on the bars in my eagerness to be away. And watched in uncomprehending horror as my stem slid smoothly out of the tiny headtube.
I managed, somehow, to stay upright for maybe a second more, before crashing to the ground. From there I could only lie still, bullhorns clutched tightly to me, watching the other cyclists look down at me as they passed, eyes filled with amusement, annoyance, some just plain incomprehension. But worst of all were the eyes that looked down, at this poor incompetent cyclist lying on the hard asphalt, and looked down with pity.