1. Running red lights. Hey, just because there's no opposing traffic doesn't mean you get to go.
2. Cycling into oncoming traffic. Some cyclists still believe that's how it's done. Uh, no.
3. Running stop signs... and not just running them but blazing through them as if they aren't there.
4. Cycling and talking on a cell phone. Totally illegal.
5. Cycling while listening to an ipod or any other mp3 device - also illegal.
I yelled at one cyclist a few days ago. Called him an "idiot" for running a red light and making a left hand turn. He turned and looked at me but didn't respond. Okay, I was in a meltdown day, I admit. I wanted to yell at the pedestrians on the bike path too - a path that's clearly marked "bikes ONLY," but I didn't. I would have only worn my voice out.
And this I've seen a couple of times: cycling and smoking. I mean, what is the point????
As for riding on the sidewalks, it's supposed to be illegal for anyone over 12. However, although I don't make a practice of it, sometimes I do pull up onto the corner to take a break out of traffic and get a drink. Or, if traffic is very backed up at a light, I can lose the light waiting way in the back, so I'll temporarily pop onto the sidewalk to go around them and get to the front of the line. I will also pop up onto it sometimes after crossing an intersection if the traffic is tight and not giving me room to get into traffic (I've been squeezed out of the flow and to the side more than once). When it clears safely, then I am back onto the road. However, I'm probably a 95% roadie.