Yes and no. I was in freelance photography before switching to programming (weird, huh?). I thought repeatedly: I can't just give up photography, that'd make me a pussy. I should aspire to do what I love.
Then I dumped professional photography and became a programmer, and I am freer, better paid and happier than I would be otherwise. Quitting one thing let me find another that is better.
I guess, the real difference is that someone (Mike Rowe) tells you want to do: don't quit, it's better. But if you don't know what's better, then you don't know if you are quitting the wrong path to pursue a right path, or what. Decisions you make in absence of a judge are always uncertain. And who has the authority to judge me?
After learning the syntax of a language (let's say C), you are left with the formidable task of learning best practices, idiomatic expressions, frameworks, debuggers, libraries... and then, how to deal with managers, how to hire employees, how to do taxes. And in spare time let's all spend a few years learning C. ;-)
Or rather, a designer is not a good designer if he doesn't have the human anatomy memorized, and no UI specialist is a good UI specialist if s/he's not a good designer. So let's all us who make web forms, go and study human anatomy for 2 years.