How come?

How come? the drunkest guy you pick up tonight, and looks as if he won't be able to keep it down, is going the longest city trip if the evening?
How come every body needs to stop off at grocer's shops when one of my friends are waiting to be picked up?
How come it is still snowing at the end of March?
How come some days you see lots of blip subjects, and on others, like today, you see none?
How come the one I do take us probably one of the worst photos I have ever snapped?
Wait though, how come this car in the picture has 2 front wheels at one side, and how come they aren't touching the ground?