It's a good idea to try and stay friendly with people on the canals as you see them again and again on your travels! But I'm afraid I've had a falling out with a boat moored not far away, which is annoying.
I was standing looking out of the side hatch as a little lad came slowly past in his small canoe. A narrowboat then came shooting by us both, pinning him to the side of my boat! I shouted to them to slow down and pointed out the little canoe sandwiched there but they just sped on, shouting back insults and one showing me his bum (ok, why DO men do this?!). Another bloke on board shouted "Slapper!" which cheered me up instantly as I'm sadly lacking in the slapper gene ;-) Although having said this, I realise I had automatically given the arse a rating of 2/10 (white, saggy & distinctly unappealing) and mentally compared it unfavourably with more lovely ones, so maybe they do have a point!