While the physical training is often the spotlight of parkour stories, whether it be negative or positive, it seems that the mental side has almost been completely neglected. To me the physical fitness part is an accompaniment to the training of the mind but it seems that if this "fitness craze" is portrayed as such people may forget that sure parkour can be fun, and yes its very physical, but parkour is inherently a physical philosophy, was developed as such for developing of the body yes, but the mind moreso than anything. but maybe thats just my thoughts.
and whoever said that rooftops are fun and gave the reason for helping strengthen his feet or whatever is just trying to make excuses for behavior it seems, sure they help overcome big mental blocks but there is WAY more not on rooftops to say that is a reason, the only thing that they may be good for is overcoming mental blocks and an adrenaline rush. when done it should never be called parkour since more often than not you aren't trained enough, are trespassing, and just generally don't even have the right idea in my eyes.
apologies if I sound harsh, its not meant that way, just expressing my opinion, I feel we are neglecting a lot of the ideals in parkour or at least not making them known publicly. maybe they are just my ideals, who knows.