Yes I can change a rear flat. (I am so proud to be able to say that). And it has made me interested in other repairs so much so, that I took bike repair 101 and 102 this winter at the LBS.

I ride alone about 80% of the time and want to be self-sufficient. Knowning how to do fix-its on the road gives me enormous confidence.

I change it with the bike upside down and could not imagine doing it rightside up. I also lube my chain that way and would not be able to lube it any other way. The first time I dropped a chain I struggled with it and needed help. By the third time I learned how easy it was to flip the bike over instead of fighting it while I was upside down.