They are unscrupulous salespeople earning fat commissions selling dud " investments " .
Talk to bike store salespeople about the kind of mountain bike you want.
I've also witnessed master salespeople who are able to obtain far more money, talent and media attention than their product deserves.
The best way to get the right fit is to go to a lingerie shop or department store where maternity and nursing items are not only sold, but are also known by the salespeople who work there.
While salespeople will not like this approach, you are not obligated to buy something simply because you were helped by a store salesperson.