When the expression "things" is more appropriate than "what"...
ex.
"things you do" vs "what you do"

Are these interchangeable? If no, how are these used differently?
Example sentences would be appreciated. Thanks!Also, I'd like to know the difference in meaning and what makes these sentences sound natural or unnatural.

Question

When the expression "things" is more appropriate than "what"...
ex.
"things you do" vs "what you do"

Are these interchangeable? If no, how are these used differently? 
Example sentences would be appreciated. Thanks!Also, I'd like to know the difference in meaning and what makes these sentences sound natural or unnatural.

Answer

In some cases they can be used interchangeably.  However, there are times when one sounds more natural.  Some examples:

"I appreciate all the things you do for me"

"Do you like what you do for a living?"

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