The first time I tried Chrome I clicked a URL from my email and Chrome opened. I was like, "WTF?". I realized that when I updated CCleaner I must have forgotten to uncheck the Chrome install. Needless to say, pissed me off. I don't like anyone telling me what browser I have to use, much less automatically agreeing to a license agreement and making it the default browser, all because I hit the next button before paying close attention. I'm usually really good at catching these sneak tactics too.
This is the main reason that I have witnessed that Chrome's numbers are so high--it integrates with so many program installs. Most people I know who are normally IE users because they don't know better leave the checkboxes checked when installing Java updates for Ask Toolbars, Bing Toolbars, and Chrome. To me it is an underhanded tactic that is far worse, in my opinion, than what Microsoft did integrating IE into Windows. I mean, to automatically agree to Google's license agreement without ticking a checkbox. Microsoft aren't saints either (Bing toolbar), but I'm not comfortable installing Chrome due to my first experience with it.