I agree that this post should not have been deleted. It asked a deep question that deserved consideration especially by those who have let some thing or some activity consume their lives in an unhealthy way. For example, A lot of people here probably sit in front of their computers for way too long, but how many are willing to admit it?
Had this post not been deleted, it would have been like a stop sign for certain people who, deep in their hearts, know that they're not feeling well. It could have helped them stop and 'look both ways' so to speak and consider whether they have indeed specialized in something too much for their own good.
The Original Post
(edited for style and grammar):
When do you think you are too involved in one field?
For example, have you ever not had the thinking power to solve the simplest problem in another field which you would have otherwise solved relatively easily.
I think it is dangerous for your 'human' development.
And although I may be reading into this a bit, when he says "another field", don't just think of work. Think of the other things you could be doing besides work that can actually bring you Joy.