No writer wants to be average. As far as your sentence length, though, average is better most of the time. The long and the short of it is this: If you stuff in too many things, you've got an overly long sentence. Readers shy away from such sentences because they hate getting lost amid clauses and commas. On the other hand, if you leave out a subject, verb and/or object, you're stuck with a fragment. Incomplete sentences may annoy readers if you use this device too often. Neither kind of sentence is ideal—usually.