I agree with Jim, no problem with competent motorcyclists who let you know they are there and I am always happy to let them pass, why spread the traffic queue misery? In return there is usually a courteous acknowledgement.
Unfortunately a lot of accidents do result from inexperienced motorcyclists taking chances, there are memorials to them on all the roads in this part of the country and no doubt elsewhere. I have never been tempted to ride a motorcycle having observed that everyone I know who has had fallen off at some point!
Ultimately whether it is truckers, bus drivers, white van drivers, car drivers, motorcyclists, push bikers in lycra or simply somebody on the back of a horse, you can't cateorise them by their means of propulsion. Basically it is a people thing. There are a significant minority of road users who are either stupid, careless or simply bloody minded and inconsiderate and they all have the power to make life difficult for the rest of us.
Colin