I always exclude as well.  In the interest of curiosity, we did do a bit of a test on one server when we were mandated (dictated is more like it)...

I'm also one of the more experienced ones that people rely on for knowledge of how things work under the hood.  I think understanding the old stuff really helps to...

The accidental many-to-many join that Jeff mentioned is a possibility.  So is an implicit cast that required you to read an entire table is another, but there are others.  Take...

I hope everyone had a very Merry Christmas.

Have you considered the space consumed by the plan cache?