Accomplishing achievements isn't about bragging...it's about doing things you'd never do otherwise...
I highly doubt I'd ever go out of my way to do 30 of the stupid little AI missions without there being an achievment...but, because there's an achievement, you know what, why the hell not do it for once?
So I start a 10 player ffa with 9 hards or unfairs, turn pirates on, and focus on trying to get as many missions done no matter how inconvenient they might be...I wouldn't want to do it all the time, but it certainly is different from the standard play...kind of sucks when an achievement gets you to try something, but then you don't even get the achievement...