'Enough' means equal to what is needed, demanded or expected. So I can't get enough of something = I can't get the quantity I need or expect. Therefore it is more similar to 'I need more' rather than 'I want more'. There is a difference between 'I need more coffee' and 'I want more coffee'. 'Want' expresses strong desire. 'Need' expresses not being able to remain without.

Yes you are absolutely right!

dui

Yes, it means you are either gluttonous or gready ;)

Yes, it means you want more.