Courtesy
It's a good idea, should you become aware that a fishing tournament is being held at at certain place on a certain date, and want to avoid several hundred rods, to plan to avoid cruising that part of the waterways that day.
Many Boaters will tell you that most fishermen are miserable, grumpy and rude, will never smile, will always believe you're too noisy, or too quiet, going too fast, or too slow, are always in the wrong position - actually 'in the wrong' full stop for being on a boat, and that they are generally a totally impossible to please waste of life sitting for hours in the most hidden part of the towpath moaning about boaters and how hot or cold it is... While this may very well be the case, just slow down, keep in the middle, give a cheery smile and pass in peace - after all, our waterways are enjoyed in many different ways by many different folk...
On no account, after being shunned by a fisherman who fails to acknowledge your cheery smile, avoids eye contact or simply scowls should you shout "Cheer up chuckles, I made the effort to slow down for you, a smile's the least you can do in return"- such fishermen have no sense of humour in this respect.