Everyone seems to assume the curve starts to shoot up at x=0. I always imagined the steep learning curve's steepness as starting at x>0, thereby creating some stalling or slow growing plateau requiring the bulk of the effort before you reach a certain point where there's a huge, rewarding jump (some "aha" moment) that releases all the build up tension. Compare A (constant, please mentally unjag it) vs B (steep):
| A _.-----
| _/ /
| _/ /
| _/ /
|/ /
|----' B
+--------------
There could be delayed steepness, but I think most people would use "steep" to refer to those moments of struggle and effort along the way, rather than the "aha" feeling of suddenly elevated knowledge after the jump. I don't think there's a term for the latter, except maybe a "satisfying" learning curve.
