Get out of your comfort zone!!
Okay, so how many times have you heard this ridiculous cliché? Too many. But guess why? No, not because it was popularized by the late Jimmy Carter. There are two reasons.
Reason Numero Uno
It's a lot more socially acceptable than saying "stop being a f***ing pussy." But, it's what everyone means when they say it. Getting out of your comfort zone means manning up and doing things that challenge you in new ways. It's the only way you develop as a mature adult who doesn't call home to mommy when they have to figure out how to do their laundry or solve their big boy calculus problems that the university professor gave them.
Reason Numero Dos
It's because it's something that all adults realize when it's a little too late in their adult lives. Holy crap, one day you will wake up from your pathetic job as overnight stock manager at Staples and realize you've never "gotten out of your comfort zone." You've been a pussy you're whole life. You need to branch out, leave home, travel, take a punch, make a speech, all that crap. But really, it's simpler than that. Example - I will readily admit this - I suck at basketball. But I also play in my work league. I am probably the worst player on our team, and it really challenges my ego to suck so bad. But I want to improve and learn to appreciate the game. So I play basketball. And I am getting better. And it helps me other areas of my life. Example 2 - I recently took up snowboarding. Remember that line in Fight Club, when Ed Norton says "after fighting, everything gets the volume turned down... you can deal with anything." Fighting is an extreme example, but after flying down a mountain all weekend on a piece of wood, hitting jumps and rails, sometimes landing, sometimes falling, always having adrenaline fueling you, work isn't that big of a deal. You'll worry less about the little things. So what are you waiting for? Stop being a melvin and go out there and do something new. Play basketball in the inner city. Tryout for the football team. Buy that girl at the bar a shot of chocolate cake. Shave your head. Don't wake up ten years from now and wish you had.