Why do users only star is they find the article interesting but not increase the vote? Also, I am new to meta stackoverflow so absolutely any comments which are productive will be helpful and more information on what meta stackoverflow is to a novice will be much appreciated.

Why do users only star a question as interesting but not upvote it? 

I am new to Meta Stack Overflow, so absolutely any comments which are productive will be helpful and more information on what Meta Stack Overflow is for a novice would be much appreciated.