So another common usage issue that I see quite a bit, even in some of the better books I enjoy, is disinterested vs. uninterested. Here's the breakdown:
If you're not interested in something--bored, in fact--then you are uninterested in it, or you have a lack of interest. An example would be, "After hearing the guy's half-hearted pickup line, the refined woman at the door gave him an uninterested look and walked away."
If you're disinterested in something, it means you're impartial, objective, and have no interest (in the "conflict of interest" sense of the word) in a matter. For example, you always want a disinterested judge in court but want the opposite in a lawyer (he is, after all, representing your "interests"). "The arbiter was chosen for his impartiality, since he was disinterested in any matters or ventures involving petroleum or oil products."
Almost always I see the problem happening one way: people use disinterest when they really mean to use uninterest or lack of interest. My advice? If in doubt, use uninterested and lack of interest. Most likely if you're needing the sense of the term disinterest, you can use impartial or objective so you don't confuse those who would misinterpret the correct meaning of the word. In other words, don't use disinterest until you're sure you're using it right. It's safer that way for everyone involved.
I hope I haven't lost your interest as you've been reading this.