Why isn't the CSS property 'line-height' letting me make tight line-spaces in Chrome?

Question

I have a paragraph tag that I defined elsewhere with a line height of 15px, and I have another paragraph tag further down the page where I want to make the line height around 10px. Funny thing is, it won't let me get down to 10px or anything smaller than that, but when I set it to 25px or higher, the line-height property seems to be working.

I checked the relevant CSS (all hand-coded) via the Chrome browser's web developer tools (Chrome's version of Firefox's Firebug) and couldn't find anything relevant. Is there a common CSS bug that prevents me from shrinking the line-height beyond a certain minimum amount?