Thinking about what makes people quit jiu jitsu on the way in and one thing that popped in to my head was the slowing of learning curve. As you progress in to blue belt you have got a basic grasp of most of the concepts and it starts to seem like there aren't any big break throughs. What the breakthroughs become are, infact, the little puzzle pieces that fill in the gaps in the techniques. Bit by bit your techniques will become tighter and tighter and your individual techniques mesh into chains. Hitting your first arm bar or triangle is huge but when you can chain them to Omaplata to Twister side to Truck to Twister to Swedish Twister, that's money.