My parents used to have a microwave with the dials you turn to enter the time. (or weight if you're doing a baked potato) One problem for me (unknown to both of us) is that I can't always quite see the decimal point if entering the weight.
Anyway, I entered the weight too high, cremated the potato and melted the microwave door...
Since then, we've bought microwaves with buttons you push to enter the time or weight.