The JS and CSS and HTML box model worked differently, the websites were displayed correctly only on IE or only on other browsers. People put text that says "best viewed in Internet Explorer 6" at the bottom of the page or straight out blocked users from displaying the page in other browsers and encouraged them to download IE - just the same thing we have with Chrome today when anything that's using some advanced API.
IE was hated after the fact of cornering the whole marketshare and making the web developers build all the websites to work on IE only.
Initially, IE was very innovative browser too and they were the inventor of technologies like Ajax, introduced in IE5. Back in the pre-hate days, the web developers loved IE and it's innovative ways that let them to cool stuff.
Chrome being still innovative doesn't mean much. Once they make sure that websites are built to work in Chrome only, they can relax and stop spending money on it and increase profits and stock prices by rent seeking.