I Have No Talent
People say "I wish I could do that" about everything. Playing a musical instrument, for instance. It's not that they <i>can't</i>--it's that they don't have the time in their lives to devote to practicing it. "I wish I could do that" really means "I wish I had the extra time to do everything I'm currently doing, but also fit in something low on my priority list, like that."