Our agent showed us over 80 houses when we moved to Maine nine years ago. Patient, witty and humorous, she is now a social friend. She has sold one of our friends some investment property and is in the process now of doing the same for another.
Now this good experience is counter-balanced by the filthy sharks that make up the Cape Cod (and Massachusetts) Realtors.
All in all, I'd say that real estate is just like any business in that it takes all kinds, good, bad and indifferent.
Caveat emptor still applies.
The biggest mistake people make is not interviewing enough agents and going with one that don't feel right in their gut.