# the nightmare bicycle imo, the most important idea in product design is to avoid the "nightmare bicycle". imagine a bicycle where the product manager said "people don't get math so we can't have numbered gears - we need to have labeled buttons for gravel mode, downhill mode, ..." this is a hypothetical "nightmare bicycle" that Andy diSessa imagines in his book Changing Minds. as he points out: it would be terrible! we'd lose the intuitive understanding of how to use the gears to solve any situation we encounter. which mode do you use for gravel + downhill?? turns out, anyone can understand numbered gears totally fine after a bit of practice. people are capable! along the same lines - one of the worst misconceptions in product design is that a microwave needs to have a button for every thing you could possibly cook: "popcorn", "chicken", "potato", "frozen vegetable" bla bla bla. you really don't! you can just have a time (and power) button. people will figure out how to cook stuff. good designs expose systematic structure; they lean on their users' ability to understand this structure and apply it to new situations. we were born for this. bad designs paper over the structure with superficial labels that hide the underlying system, inhibiting their users' ability to actually build a clear model in their heads.