I get really sad when people say, 'I'm no good. I haven't been cast in a pilot.' It doesn't mean you're not good; it just means someone hasn't seen you yet. It doesn't mean that in real life you're not the greatest actor.
My best advice to actors is if you love acting, do it every chance you get. Success does not mean success. All that matters is whether or not you're doing your best to entertain. The way this business works is all about luck and timing.