Making a save system is hard

I tried using the unity JsonUtility class to save the data for my game ( many problems arose from that decision ).

I don’t completely blame the JsonUtility class for my woes as part of the fault is mine,

I did not fully understand how JsonUtility class works and had I decided to using this thing from the beginning I would have changed how I made the game (in other words every class would have a struct that contains the data needed for it to work) 

I lost 2 days of work to trying to make JsonUtility work for me but in the end I had to discard everything I did with the thing do to the fact that after using it some of the classes would have null variables making everything break

And also it took another 2 days to implement the save system after discarding the things I did with the JsonUtility class

TLDR : lost 2 days of work and took another 2 days to get back to where I was