Ted is dating a girl with a very annoying habit, which leads to everyone in the group pointing out each other's flaws. Meanwhile, Marshall is desperate to find out if he has officially become a lawyer, as the results of the final law school exam are online, but he has forgotten his password. Barney goes to great lengths to cheer him up, which Marshall does not appreciate at first.
I really like how this episode balances the fun and the more serious storyline about Marshall's future. There are lots of laughs about all these little annoying habits and character flaws, but they don't matter when it comes to your friends and the really important things in life. The end of the episode reflects that well. Overall, a fantastic performance by Jason Segel, who handles the more emotional parts well and on top of that probably gets even more laughs than Neil Patrick Harris this time.
Now let's take a look at the flaws to our main characters that are introduced in this episode. As it turns out, most of them are true to the respective character and the continuity of the show.
Lilly's loud chewing: That one is newly introduced, at least I didn't notice it in previous episodes. Of course it is exaggerated here for the laughs. Marshall's facial expressions when he has to confront Lily about it for the first time are just hilarious. Hopefully he gets used to it by the end of the episode.
Ted, the Corrector: This habit fits Ted's character very well, and we've seen it before. We already know it from his pretentious college days ("My parents live in Ohio. I live in the moment."), and obviously he couldn't quite shake it off. Good continuity on that one.
Robin: We have seen her use the word "literally" before (possibly even misuse it, but I'm not sure about that since English isn't my first language), it just didn't strike me as an annoying habit. But Ted dated her for a year and he is rather thin-skinned when it comes to misuse of the English language. So his annoyance is justified. Interestingly, in this case the most affected person is the one to point it out, while in the case of Lily's, Marshall's and Ted's habits, the most affected person (Marshall, Lily and Robin, respectively) has previously been completely oblivious to it. But if someone would point out such a habit of his own long-time girlfriend, it's Ted, the Corretor.
Marshall singing about everything he does: Another big continuity bonus point. This was introduced as early as season 1 episode 3. A great callback to Marshall's greatest hits "Driving to Philly", "Being a lawyer better be awesome" and of course "Our relationship's built on mutual trust". I just don't see how this would be annoying. It was hilarious back then, and it still is.
Barney: Poor Barney gets called on three offenses. The high-pitched voice is new and probably just exaggerated for this one episode, like Lilly's chewing. The catchphrases have always been part of his character, though. Again, it was in season 1 episode 3 that Ted (who else?) first pointed out that Barney was "too liberal with the word legendary". Barney spacing out has been a recurring theme as well. A particularly funny example is in this very episode, when Barney starts to lecture Ted about how you can get blind to a person's flaws when you're attracted to her, and as his story unfolds, he ends up simply bragging about his qualities as a lover. "And what does this have to do with Cathy?" - "Who's Cathy?"