Do you really use all the stuff you get from your registry?

I thought I would have some fun and start a registry for the weddings.  I figured it would be fun to pretend that I was re-doing everything, plus one less thing on the list.  I didn't know where to start so I started looking up list guides.  Now, I know less of where to start and can't help but wonder, "Do you really use all the things you get off your registry?  What should I not even bother putting on and what is your one, I didn't know I couldn't live without item?