One must achieve a balance. Nor is an existence without width. And one also needs depth. Life is something to be enjoyed, not suffered through. There is a rich tapestry of experiences out there waiting to give depth to your life, and to gain this depth we must sometimes sacrafice length or width.
Depth alone is no good either.
In an individual's life, as in a society, an ecosystem, or a set of chemical or mathematical equations, one must have balance. One must be free to pick exactly what proportions one wants the faces of one's life to have. Maybe you want to live long and wide but not deep. Or maybe the other way around. It's your decision to make.