The best salesperson isn't the one whose customers are leaving the shop smiling just like a TV advert where buying X or Y will solve every problem in life, but rather the one whose customers leave the shop angry after having purchased this or that product or service, because that is an indicator they were squeezed until just before the point they tell the seller to stick their product somewhere and leave for the competition. Not that I like it, but that is how I see it.
Low trust == maximize mechanical power and optimization
Higher trust == invest time, relationship-building and lower individual transaction profit over a larger volume of profit
Few consumer sales interactions fall into the second category.
I know what I need just gimme the 100 MBPs plan!
A good salesperson will make sure the choice process is relatively quick and painless. You will feel good afterwards knowing that all the 125 aspects that differentiate this model from the other ones are not that important. The one you chose runs your favourite apps, integrates well with your car and your home entertainment system.
Understanding this and learning how to sell helps in life, incl. negotiating architectural changes with non technical decision makers.