It comes down to one thing and one thing only... They don't have a passion for it, Plain and simple. No matter all of the reasons people have listed, if they have a true passion for our sport then they find a way to make it work, no matter what. All I think about is BJJ, when I am in the shower, sitting on the train, hanging with a chick, before I go to sleep, at work... All of my closest friends train, except my best friend from high school, and even my boy from high school loves watching the highlight videos I send him, and could name most submissons that he sees on tv. Shit, even 3 guys I became friends with from my last job are all blue belts under shaolin now, because I made them come take a free trial class. They are now 3 of my best friends, and also never shut the fuck up about Grappling. I even broke up with my ex who i had dated for 5 years, because she told me to choose between training less and being with her. Without even 10 seconds passing I told her, and I quote "I guess you made your decision then" and I walked out the door, and headed straight for the gym. Two years later I am still heart broken, because of that woman. Serious fucking Johnny Cash song heartbroken over her, developed a nice little pill addiction/drinking problem over that woman. But I beat that nasty shit part of my life too, she still won't take me back, but my mats/training partners/coaches are always there with open arms. So, like I said, it all comes down to how much do you really love getting you ass kicked 6 days out of the week.