Katie Holmes hops into the ranks of other famous women to guest star on How I Met Your Mother and she fits along with them: she doesn't really belong, but the writers don't give her anything demanding. The slutty pumpkin from all the way back from the first season is revealed, and after 10 years of waiting, it's a disappointment for both parties. They both want to make it work after so much longing, but in the end they know it isn't right. Thus, ends another chapter in Ted Mosby's never-ending quest to find the Mother.
Barney turning out to be Canadian was kind of pointless, but the writers laid it on thick and Robin pokes fun enough times to make it worthwhile. I'm a big fan of the Canada jokes, so it had me very amused. Likewise, Lily being crazed won't have any affect on the future, but she eventually realizes the suburbs aren't where she belongs, and the show returns to equilibrium.