[kangaroo5383]

Ha! That's exactly me. However I'd suggestion being jill of all trades and master of 1.

In my experience I find it more helpful to be really good at one thing but can do a lot of different things (full stack, design, product) to get the job done, you're more appreciated that way. In my case, iOS is my One.

[GFischer]

That's the "T-shaped" approach atsaloli mentions :)

http://darrennegraeff.com/the-importance-of-t-shaped-individ...

[koide]

And now there is this new trend about the pi-shaped person, master of two. Which is reasonable if you can manage.

[sharemywin]

I would agree with this.