Cycling Idiot

Royal Mail bikes as you know are old, but stout beasts. On the front they have that nice little basket to hold the huge bag of mail the postie will endevour to deliver that day. This is a fine idea.
However, at the end of the day the postman has several of these bedraggled red bags on his bike. 'So?' You might ask, but probably will not bother asking, as you are not reading this are you? Anyway, at the end of the day the postman has too many bags on the front of his bike. There is little in them, except packets folk are to pig ignorant to be in when they arrive, and 'signed for' letters, and the occasional missort, which we will not mention as they are not supposed to happen. So, the man has five bags on his bike. A handfull of light letters in the topmost bag, and heads for home.
Home is the sorting office, you know, the one at the bottom of the hill. All he has to do is drift down the hill and round the bend (something he knows all about going around I can tell you) and up into the bike shed. Simple. Only an idiot could fail to accomplish this simple, straightforward chore.
Ah yes, there is one thing. The wind.
See, as you go forward the air pressure around you meets you. On the bike this 'wind' is much more noticeable and can hold you back. Indeed, when going downhill, as our hero has to, means he meets a bit more of this air coming up to meet him. This means the topmost bag, you know, the light one with not much in it, tends to rise of the basket and fly up into the air.
Simple again. Put out a hand and push it back down. Easy.
Well, yes. But, if the bag begins to float to the postmans left side, and a taxi is right behind him at the time, and he is negotiating an obstacle, and he then loses control of the bike and the front wheel juts against the kerb, then what?
Then I can humbly tell you, he loses it altogether!
He stops pushing the floating bag, sticks a foot out towards the ground, lets go the bag, grabs the handlebars, far too late, feels the bike going from under him and heads for a meeting with the pavement. That's what!
Why is it he asks afterwards, that the taxi does not stop, GIT! But the next car does, enquiring after your health, and wondering if the taxi had hit you. Again I ask why is it that behind him are several other cars, each occupied by men sneering with straight faces and leaving you feeling embarrassed and with a bruise on the shin?
I don't know, but I am that man. Where's the germoline eh?