Squarepebbles, your posts are intriguing, as I have two who are so close to what you describe, I could have written your post. For years I was too soft on DS2 as he is so dreamy and vague and forgetful. He hates being pushed. But when it came to 11+ he had to be pushed (not hard - just one practise paper a week.) He did it, got into his first choice school and was over the moon. For the first time he saw that doing something you don't always enjoy at the time can make you feel fantastic long term. His self confidence has gone through the roof since he passed the exam.
Recently, we started running. He hated it - whinged, teary eyed, said he couldn't breathe, felt sick (within first 30 seconds of the run, so I wasn't concerned he was being overly pushed
) but we just kept him at it, kept saying, 'You hate it, I know, but we're seriously unfit and we need to get fit' until he realised that how ever dramatic he was being, the run would still take place.
By week two he was asking to go on runs. He's a sedentary gamer and dreamer by nature. I learned from 11+ that I just had to ignore his protests - not fight or cajole, or try to change his mind, but just not give in, keep him going. In the end he was as proud of himself and motivated as his self disciplined brother, who gets up, dressed, does 30 mins piano practise and all his homework before anyone else has even grunted and stuck the kettle on.
The interesting thing is, as he gets older, he's starting to see cause and effect - hard work means great results, effort means fitter - he was man of the match at rugby on Sunday for the first time in two years - he saw the link between running, getting fitter and being a better team player. I'm hoping he'll start making the connection without being prompted by us, in time. Will be really interested to read Tough's book.
The only difference I can see in their parenting (and it probably is pretty huge) is that DS2 was very poorly from birth and needed a lot of attention in order to survive, whereas DS1 was left to his own devices, and a lot was expected of him, because his brother was so needy. It did make me baby DS2, and make DS1 self reliant from the beginning. But in terms of love, support, attention since then, it's been as even as can be. They're just very different people. Sounds ott, but even in antenatal scans, DS1 would be waving and booting his feet around, whereas DS2 would be sucking his thumb, all tucked up.