I can not really think of a protagonist I have cared about the most, because I do not read a lot because I am picky. But, I can tell you what makes a good protagonist, or just a good character. Readers like to get to know the character they are reading about. They like to know how they would react to certain things, what they look like, how tall or short they are, etc. Being able to connect with a character or get a feel of what the character is like, helps the reader understand the character more and be involved in the book, and what happens to the character. Characters who have personalities are much more interesting and a lot less boring.