Why would you share your wealth with the poor?

I would really like to share my wealth with the poor. That's because I believe that we should be thankful for this gift we got, health, food, shelter and other needs like money. Most of the needy/poor people became poor because of wasting food and/or money. For example, many rich people waste their money on stuff that they don't need or throwing the rest of your sandwich in the trash. Instead of doing this, why don't you use your extra money on poor and needy people? Or at least make the remains of your sandwich to the proper shape and give them to a poor. 

This is a short summary of what I think.
Do you agree? Why or why not?