In a blue of frantic worry, Usa opts to borrow Mayumi's phone to check in on whether Ritsu is okay, and although she isn't okay and is enduring a nightmare of a time it's nothing that she can't handle, although Usa's message is both appreciated and gives her a perfect reason to make her excuses and leave. This event, however, is the final straw in Ritsu's budding friendship, and thus she has to find a way to put it to an end - a decision which is it as hard as it sounds, although ultimately it only seems to cause any real emotional harm to Ritsu herself as she finds herself assuaged at sadness that she maybe wasn't considered to be such a special friend after all.
In this situation, there's only one thing for it - to get drunk. Although this probably isn't a deliberate decision on Ritsu's part it's how things end up, and it seems that drunk Ritsu is something of a loudmouth who has no problem telling all and sundry exactly what she thinks of them, or indeed for sulking about a lack of cakes. Ultimately, and in a rather roundabout way, it does seek to close the gap between Usa and Ritsu a little further, as the two finally swap phone numbers of nothing else to give us the closest to a happy ending this series was ever liable to.
Now we're at the end of the series, it's probably fair to say that The Kawai Complex Guide to Manors and Hostel Behaviour boils down into two aspects - the bits with Ritsu at their centre, and the rest. Watching Usa and Ritsu's relationship develop (for better or worse) always provided the show's most enjoyable moments, and in these times the rest of the cast did a great job of moving things along with their one-liners and snarky quips. However, when those individuals became the main characters, the series never had quite the same air about it, as the humour became predictable and the entertainment value dipped - not excruciatingly so, but enough to become noticeable and even a little frustrating on occasion. That isn't to take away from the fact that I enjoyed watching the series overall - it succeeded more often than it failed, and even its weakest episodes still had their moments, to make for a fun comedy in a season which didn't really have too much of the stuff to offer as a whole.