Seems like still quite a number of people do not agree that Risk is dealing with something you don't know (read the post about risk here).
So I would like to repeat that yes while Low Risk Low Return and High Return High Risk are TRUE but if you think it that way, you may just settle for "whatever it is, it is !"
For example, you may think you are not a risk taker, therefore you will never get a high return !!
My 'additional' point made to above truth is that, you should still make effort to learn the next risk in your portfolio so that the more you know, the better you can manage that risk until it becomes insignificant compare to its potential return.