This is one I am not particularly proud of (or am I)? It is a long tale, sorry, but necessary to get the comedic effect.
Driving to work one morning, about 7 months pregnant. Horrible, horrible drive, with everyone trying to nip in front of you, cheat queues, at the same time as driving too fast in all the wrong places. Driving along on the dual carriageway, just where three lanes change to two, a car flew past me and nipped in front just as the traffic was starting to slow down for a traffic jam. Imagine me having to brake so hard the front of my car almost made a groove in the road, and the back of the car losing contact with the tarmac.
WELL!!! I got out of the car to remonstrate with Mr Suit, by which time the traffic had started to move along again, slowly (but not slowly enough to prevent me from having to break into a bit of a trot to catch up with him). I did catch up with him, flung open his door, grabbed him by the lapels and lifted him out of his seat, swearing like a fishwife and calling him all the idiots under the sun
. He looked utterly terrified and apologised profusely. Threw him back into his seat and walked sedately back to my own car, which was by now quite a bit further away than I had imagined. (A driver in an Artic yelled out of his window "Well done, love" with his thumbs up, which made me feel a little less embarrassed - thank you, that lovely man) 
Now, this road, as said, is very busy, with everyone vying for position. But the traffic had come to a complete standstill, with everyone waiting behind my car, huge gaps in front of it, in all lanes. Put my hand up to all commuters to say thank you and sorry, carried on to work.
Boss says "Morning Evans - how are you?"
"Fine thanks" says I
Him - "How was your journey today?"
I tell him, and he reveals he was in the car behind me (he'd apparently slid down behind his steering wheel).
Me - "Thanks for coming to help me then"
Him - "Oh, you appeared to be doing such a good job yourself, you didn't need my help" 
It has given us a few laughs over the years, and I can only hope that Mr Suit was a bit more careful about his driving from then on in.
(Sorry - that's almost a novel)!