To assist in the ongoing effort to better articulate a set of social norms for the endless variety of circumstances one encounters on city streets, we’re passing on this request from a reader. "Midtown Biker" asks for advice on the best way to handle these situations:

1. Another biker is riding the wrong way on a one-way street (West 90th Street) and
   hogging the bike lane. I tried "Please ride with the traffic" and got cursed at.
2. I’m riding in a bike lane. A car cuts me off, then stops short,
   double-parking in the bike lane. The street is now impassable. I tried, "Please
   don’t block the bicycle lane." The doorman from the driver’s apartment building
   said to the driver, "You do whatever you want. You want to park here, don’t
   listen to him." Any suggestions?