Why do you pay someone?
For their actions or the benefits
That you would reap out of their actions?
Why do you thank someone?
For their help or the way
You would feel for thanking them?
Why do you get angry at someone?
For their (in)actions or the
Effects of their (in)actions on you?
Why do you care for someone?
For their well being or the measure
By others of your care?
Why do you donate to good causes?
For the benefits of the recipients or the
(Monetary)Benefits you get out of the donation?
Should it matter why people do what they do?
Note : Paraphrasing inspired by this
agamthedal 