The most important difference between Level 1 and Level 2 actions is that Level 1 actions tend to be additive, while Level 2 actions tend to be multiplicative. If you do ten hours of work at McDonald's, you'll get paid ten times as much as if you did one hour; the benefits of the hours add together. However, if you take ten typing classes, each one of which improves your ability by 20%, you'll be 1.2^10 = 6.2 times better at the end than at the beginning: the benefits of the classes multiply (assuming independence).

I'm trying to think of anything in life that actually works this way and I can't. If I start out being able to type at 20 WPM, taking 100 typing classes is not going to improve that to 1.6 billion WPM; neither is taking 1000 classes or 10000. These sorts of payoffs tend to be roughly logarithmic, not exponential.