On achievements:
There are more or less three kinds of achievements:
1. OCD where you have to get all the trinkets and all doohikeys, including achievements
2. Tracking your progress through the game, as in "beat level 1", "beat level 2" and so on (that's like half of all achievements in Ubisoft games). I personally find them pointless, because it's more or less amounts to time you spend on a game and where's the merit in just time spent?
and yes --
3. Virtual e-peen bragging reason should NOT be discarded only because it sounds childish. I worked for this dammit -- why can't i show off the fruit of my work (or play in this case)? When i go above and beyond normal playthrough i want to see that i will receive some, any kind of manifestation of my efforts. Not because i am arrogant (though there is a bit of a pride in that too), but because i want to konw that at any time i can go back and look at it and remember the times i did that or this.
I think it's similar to Scrooge McDuck:

Scrooge bathes in his money not only because he has money fetish (though there is some of that too), but because he remembers the story behind every single penny and how he earned it.
Platinum-system on Playstation systems caters to OCD reasoning, because the system implies that you can and SHOULD get all achievements to reach Platinum. I think it's a mistake because this devalues achievements into completionist items. Some achievements are
supposed to be hard, even impossible. And it's completely okay.
Neither Xbox and Steam make such a big deal around getting all possible achievements.
I think MiiVerse does a good job of catering to point 3, because if game has some kind of in-game achievement or rankings tracker you can make a screenshot out of it to save it, along with some comments.
Some of the achievements on Steam has gone bad too, TF2 in particular is rife with special servers that will help you to get all achievements and where you can spend time "idling" doing nothing (TF2 rewards player for time played with random drops, so some people enter idling servers and leave computer on for hours to get more hats).