Most of our smaller quilt shows have yummy home made sandwiches, slices and cakes for morning tea and lunch, and that is a definite bonus! I also like to buy 2nd hand quilt magazines (often 3 for a dollar), and other people's left over fabric pieces (the local guild usually has a fund raising table with donated material).
So you don't need to go to a major quilt show to enjoy spending a few hours, and as others have mentioned, you can often find inspiration such as a new border concept, or original colour combinations. I go to every quilt show I can.