1. Page load times

2. Ads, interstitials, popups, screen-coverers

3. Those annoying bars at the top or bottom of a page that move with the page. Or the ones that pop out when you've read 2/3 of an article.

4. Auto-playing video and ads with sound.

5. Javascript exploits are uncommon (tinfoil hat)

I want a flat web, and disabling Javascript gives it to me. Thankfully, Chrome lets you whitelist sites.