nozzle on air compressor
 

While I'm dubious about it's usefulness to fix a flat, I thought the included air compressor would be a handy thing to have in general. Well, the other day I went to use it to add a little air to my motorcycle, and I couldn't get the nozzle to mate right. I tried to screw it on, but all it seemed to do is let out air once the pin hit and the tire just steadily lost pressure (even with the pump running) until I gave up and had to take it to a gas station. Am I doing something wrong with this thing? Are the valve stems on our cars a different size? Am I just an idiot?