It's good, a completeness of a human, and of existance, to experience all the emotions,  each of them in their time.   I do not mean completeness as an ending, I mean as being whole.  In Hebrew that is שלם, shalem.  Related to that arabic unicode word by the way.  There is indeed a joy in existance. 
I spell that existance.  Not existence.  Not sure why yet, but it seems more correct to me.  A varient of the "ance", "ince", "ence" and "once" and even the rare "unce" endings in Englsh.
Yeah, "varient" !  Anyway for me, for many decades after an NDE I  was not quite able to experience sadness and then after a second NDE decades later, no longer very able to feel fear.    Instead of sadness I would be angry, and but there was no replacement emotion for fear.  I had to train myself to intellectually cognate fear, and now, 12 years later I do again feel fears, but not as strongly as b4.