Teen motivation to work for a goal seems to be a parent's responsibility now and I'm stumped. With everything at their fingertips there is still a great disconnect from what they want and how they expect to get it.  Earning it and true independence doesn't seem to be in their vocabulary.. or maybe it's just my sons.  
After the all the behavioural battles with my oldest son to graduate high school I wanted to be stronger for youngest. He is different but neither one wants to do the work to get good grades and earn all the rewards that go with it. They want cash, vacations, clothes and especially a car without any effort on their side.  Their desires for independence is to have the best social life possible right now with no regard for their future... and I'm only talking of their next year of high school.  This me me me, right now, immediate gratification attitude forces me to constantly impose choices and consequences instead of them just doing the right thing. They can't see that they could get anything they want if they just did it the right way.  It's so difficult to not compare to myself at their age.  I wanted out of my parents house but I knew I had to do it on my own. Get a job, buy a car, get accepted to the school I wanted and even find a way to pay for college which I did.  My guys want to stay at home but be able to do anything they want with no consequences.
Today my son proudly text's me his school ID and schedule to show me he has registered for his sophomore year of high school

About 4 years ago I trained for my first half marathon. At the time, the boys were 11 and 15 years old. As a single mom, this was the first time I felt a little freedom!   I was really slow at first and I would come home really tired but I always felt like I had accomplished something most people at 46 didn't do... run a mile for fun.   The boys were always  full of advice since they had been running track since 1st grade, they were experts...