I really enjoy finding places where the roads have been relocated. It’s living history to see how problem areas have been fixed. This seems to happen a fair amount with the TIGER import in the US; I guess it’s hard for TIGER to know of every change over the years. Here’s a good example of smoothing out a sharp corner (view the Bing! imagery to see where the road used to go). Something for the future archeologists to find too. :)

osm.org/?lat=44.185771&lon=-123.249265&zoom=18&layers=M