I love to help people, but sometimes you have to quite doing so because trying to teach them over and over again simply won't work. I have a few of these persons in my environment, and trying to advise them over the phone simply won't work because they don't listen to what you say, and also lack the clarity of mind to properly answer the questions you ask.
And now my rant is over, and I have enough energy again to still assist again, when the next request comes in! Because I simply love to help, even if it takes up time I'd rather be spending on other things!