OK. Imagine you're relatively new to Washington. Your extended family has tricked you into going to the zoo with them. You're giving your second cousin instructions on how to get to your group house on 49th and Brandywine from Connecticut Avenue. So, we're driving, we spot Brandywine, and we take a left-hand turn. After all, it's my street.
But it's not my street. Taking Brandywine from Connecticut Ave. will lead you straight to Wilson High School. See. Brandywine starts up again about a half mile later. Same thing happens to you on Chesapeake, Davenport, and Ellicott.
A few years later I was staying at an apartment complex off of Macomb and Massachusetts. At this point I had a better feel for DC. My family knew my cross streets, but I was very particular about one thing: If you see a Macomb, avoid it at all costs. Why? Well, Macomb starts and stops as it pleases. That's three Macomb Streets. And none of them are connected!
The confusing roads persist in other parts of town. In Friendship heights there are two 42nds and two 43rds. There's a 9 1/2 Street by the 9:30 Club which, incidentally, has its own set of problems. The numbers are just as bad across the Anacostia which features two 31sts and two 32nds.
I guess my point is this: This is an abortion of a grid plan! It seems like proper city planning would prevent this silliness. To think, this is a city that depends on tourism dollars! This "system" is confusing for people who are new new to DC. Heck, it's confusing for me. When I was looking for housing in January I walked down 42nd Street instead of 42nd Place. Result: Knocking on a lot of wrong doors. (A big apology to that family whose baby was asleep.)
I understand that it's kind of fun to watch people who don't know DC as well as they should get all confused and disoriented. But they deserve a little pity. Washington has made it as difficult as possible with its duplicate streets, no J Streets, and traffic circles. It can be pretty easy to get lost if you don't know the city's idiosyncrasies like the back of your hand. Just another negative quality of DC to throw onto the pile.
Most of my examples are limited to the 20016 zipcode. There are probably a ton of other examples of this. Feel free to leave more examples in the comments.