Bicycles.

I do get the whole bicycle movement.  It's good exercise, it's good for the environment etc.  I understand.

(I don't ride a bike - downtown Toronto for me is just too busy - I'm kept busy trying to be aware of everything going on around me just walking.)

I hear a lot from bicycle activists (on TV, magazine articles) about unsafe conditions for riding and how dangerous car drivers can be for bicyclists.

But I'm a senior citizen and a pedestrian and there are many times when I feel really threatened by bicycle riders.  
They ride on the sidewalks (even in places where there are bicycle lanes on the road).
They come to a corner at a light and then cut you off making a sharp turn into the pedestrian crossing which somehow suddenly is a "bicycle lane". And then give you a dirty look for being in THEIR way!
They make a turns right in front of you.

I've heard bicycle riders say, "I know what I'm doing and I'm in control of my bike so pedestrians don't have to worry".   That seriously is not a lot of comfort and it certainly doesn't feel like I'm safe when they go barreling down a crowded sidewalk or fly out of an alleyway without appearing to look anywhere but straight ahead.

I don't drive in the city anymore but people I know who do find some of the stunts bicyclist pull on the road totally incomprehensible.

And yes, I have seen pedestrians do some pretty dumb things on the street as well.