The Worst Advice Ever Given:

"Follow your heart" 
 is almost always the very worst advice a friend can give you if you're teetering on a major decision.I know they mean well - it's similar to 
"follow your passion" - Oprah-esque.

But, frankly, most of the world isn't granted such folly. Most of us have jobs that are very difficult. Many folks have terrible bosses. We have lengthy commutes and bills to pay.
Keeping loyal vows in our marriage doesn't always feel like what the heart craves. Quitting a job is rarely the prudent thing to do. 

Running away from home, avoiding bills, spending a paycheck, eating too much, blowing off the gym, walking away from friends in need, staying in bed all day, giving in to co-worker lust...these are normal human desires that must be overridden by our executive function, the more mature, adult brain.

Impulse control, self-discipline, putting off gratification - these are skills suggesting that we have matured in the ways that most likely guarantee happiness, stronger relationships, more intimacy, and better physical and financial health.