In How I Met Your Mother they made a big deal of Marshall and Lily's trip to Rome but then we only see a very short scene of them in Italy. I would have expected at least a couple of episodes. So what happened to it?
In HIMYM most episodes have all the characters at one place. Keeping Lilly and Marshal away from the rest of the characters would not be that much fun I guess
How I Met Your Mother is told from Ted's point of view. He didn't make the trip to Rome, so he wouldn't have a lot of details about the trip to tell to his children years later.