Weber's Law

I've started studying for my Masters in Computer Science this year and one of the courses I'm taking is Image Processing.
One of the early lectures was on color perception and so I was introduced to Weber's Law. In short, the law argues that perception of change depends on the relative change, for example, a candle lit in a dark room will probably be blinding, the same candle lit outside on a sunny day won't be noticed at all. Anyway, my explanation is probably a bit lame so just check out the link.
I always like to study about these things that show us how sophisticated human body (and nature in general) is, and how decades of research are spent to try and solve an issue that is already solved(we just have no idea how) in natural systems .

Few weeks later, I'm after a Judo session and my instructor tries to motivate one of the kids, he has to main points:
1. You're not supposed to suffer from practicing Judo, but on the other hand, you have to know what you want to achieve and realize you will have to put in some hard work to get there. Well, this is mostly a good approach to life but not what this post is about.
2. As you get better (the kid is no rookie) it's harder to tell you get better and this can sometimes be frustrating. Out of the scope and probably not subject to quantization but that's definitely a reincarnation of Weber's Law.

Actually, as I was listening to the conversation I thought it might as well be a discussion on relationships.
Only this week I realized the same applies for becoming a professional too. I recall that a month or so after I started doing my job on my own (not being a trainee anymore) I was excited to see how much I've learned and done in this relatively short period (and all - almost - on my own). Well, I'm definitely not there yet, I still learn new things daily and get thrilled by solving problems, but the sensation of progress is obviously not the same as at the beginning.
I think this is an interesting dilemma, anyone wants to be the top expert in his profession but once you get there, where's the excitement of learning new things and solving new issues?
Luckily, there are so many aspects in this line of work that one can always find something new and stimulating to learn, and this is what one should do if challenge and satisfaction is what he's after.

Personally, I think it's nearly impossible to become an expert of this caliber, but this Weber's Law stuff just got me thinking.