Obstacle reduction refers to reducing the feeling of discouragement of users during the process of product usage by designers when designing. Most of all, the key of this one of UX design skills lies in empathy: designers should forecast the problems users may encounter, identify the reason why users feel anxious and thus turn potential problems into opportunities to please users.
Paradox of choice tells that more options leads to fewer purchase decisions. Overwhelming your customers with all kind of choices might not be good. Less is more. In one test, by removing less important product categories and promoting the hero products in focused tab view instead of carousel, more purchase were made. And the result was not surprising.