And he saved me from spending $900 extra on a tractor I didn't need.
That right there is a MASSIVELY undervalued service. I don't have much first hand experience from the service industry, but from what I've heard from others, managers don't like it when their staff "down-sells" or advises customers to go elsewhere. It's sell, sell, sell. Upsell, upsell, upsell.
When I go to buy something and they suggest a cheaper item that fulfills my needs or suggest a competitor when they don't have the item I need in stock, that makes it MORE likely that I come back. It also makes it MUCH more likely that I'll recommend the place to others, because I know there's a decent chance they won't get screwed and walk out with some crap they didn't need.
I still prefer actually asking for help instead of getting a pushy sales person asking me if I need anything every couple of minutes.