Saw this a little while ago - only remembered it recently.
There is a cycle path on my route to work which runs along quite a busy road. Whilst on my way to work, I saw a cyclist nearly get wiped out by a rather large cement mixer lorry.
The cyclist, rather understandably, was less than pleased. He cycled quite quickly to catch up and then promptly spat at the cement mixer. Impressively he did manage to hit the lorry.
However as the lorry was filthy it was doubtful that the driver would even have noticed.
I do feel however that small acts of defiance should be celebrated.