The time you need to find out competitor pricing (quote) is also inefficiency. Ideally (unachievable of course) all the options and prices (and fair comparison based on product utility only) is immediately available for any customer upon demand, with zero time spent on research.

Irrational behavior is when customers choose a product not for its utility divided by price (but note that pleasure is a type of utility).

Now, exactly how to calculate aforementioned utility is a big pandora box, the whole schools of economists grew up on that question.