I am 23 years old and today I watched a youtube video to learn the proper way to cut up an onion. I cook a lot with onions, maybe two or three times a week, and before today I didn't know how to dice an onion except to slice it into rings and then hack at it a lot. Seriously.

Is this evidence that I am fundamentally unable to cut an onion? No. After I watched the video I went and did it. It's just that in the past I knew enough to get the job done and so learning anything more on the topic didn't have a huge priority.