Hypothetically speaking: if you were in your sister's wedding recently, had spent 15 minutes putting on makeup for the occasion, and then were asked by the makeup artist "Are you done with your makeup?" Then, when you answered "Um, I guess," the makeup artist replied with "Would you mind if I highlighted you a little?"
... then you might come to the conclusion that wow, after 20 or so years of wearing makeup, that you don't really know what you're doing. Okay, I confess, this happened to me. To make things worse, the "highlighting" session of which she spoke took longer than my original attempt at applying it myself. After she was done, I didn't feel like myself. Well, I felt like myself, but with a face full of spackle. Shimmery spackle at that.
Ah well. I suppose I've never claimed that I was good at putting on makeup in the first place. (Unlike a good friend of mine, who believes that putting lip liner on without a mirror is her spiritual gift.) I'm good at other important things, like watching reality television and buying shoes.