The microwave in my college apartment can heat food for one minute and eighty seconds. My roommate tried it one night, and it counted down from 01:80. It has specific baked potato, pizza, beverage, frozen dinner, cook by weight, defrost by weight and speed defrost buttons.
I've never used a more customizable microwave in my life. Unfortunately, it's not customizable in a way that's useful. I would give up all those buttons for the one I used the most at home: "30 sec."
Sometimes improving a product doesn't come from adding more functionality but instead from re-bundling existing functionality in a way that makes it less mentally taxing to use.
Forcing the user to control how long to heat their food every time they use the microwave adds a small but noticeable cognitive load to the process. On the other hand, having express buttons that simply heat for 30 seconds or 1 minute removes the mental friction of deciding exactly how long to cook the food. Such buttons don't take away any functionality from the microwave; you can still enter exact times if you want, but they allow the user to bypass the decision fatigue of picking an exact number 95% of the time.
The beautiful thing about an express button is that you barely have to think to use it. Of course, by going with a "one-size-fits-all" option your food may come out too hot or too cold, but that can happen even when you decide precisely how long to warm your meal. Most of the time, I don't need my food to be heated to perfection. I just need it to be good enough.
Good design limits the mental toll of using a product, not with extraneous features or dumbed-down functionalities, but through thoughtful simplification of its most common use cases.