As an IE fan I was annoyed that they stole porn mode (IE announcd InPrivate before chrome existed). I still know quite a few people who think Chrome invented incognito and that IE ripped it off.

Now that I look it up, apparently the idea started with Safari, but it didn't get much press.

I think the biggest innovation in chrome was how rapidly they shipped. Chrome copy-catted on hardware accelerated rendering and porn mode, but shipped first in both cases.