Joe Kraus once said in a talk that companies, especially startups, need to triple down on what they're good at rather than focusing on all their weaknesses - that's really the only way a startup can win since it can't be better than a big company at a lot of things, but it can be head and shoulders better at just one thing. I'm not sure how this applies to people, especially since balanced people can bring a fresh perspective to things (i.e. a programmer with some creative background might approach a problem in new and interesting ways).

Without arguing the efficacy of the TigerMom approach, this is indeed why a lot of parents force their kids to do something - you may not have a knack for it at first and be tempted to write off that it just isn't for you, but you need to put in a little more time to really figure out what your true learning curve for something looks like.

One interesting question is whether you really love doing something or just love doing it because you had a knack for it initially and picked it up quickly (which results in a positive feedback loop: you spend more time on it and get even better at it compared to the things that you didn't have a knack for at first). I think college really hammered that home for me - before, I just really liked a lot of math of science because it seemed to come naturally, but to find what you really love doing, you have to hit the wall and see if you enjoy it when it becomes a struggle.