This is an episode that was follow up from two episodes ago. For me it goes back to what Ted said near the end of season one. Sometimes you do something knowing it's wrong but you do it anyway. Before Ted and Robin moved in together, they had a big fight. I understand all people fight in relationships, but the fight they had was different. The kind of fight they had does should not result in a big decision they had. You also get to see the end result of what would happen with what Robin did with some of the things Ted tried to do. I also understand that when you move in with someone, you make some sacrifices. , but Ted what had to do crossed the line a bit. Even with Robin giving up her dogs.
The episode itself was funny. When Ted received from a call from a "mysterious" caller, it was a funny scene. It was kind of like crime show but done in a funny way. It was just as funny when Ted did the same thing to Barney. You also get to see why the decision to move in together was not a good one with everything Ted and Barney do together. Like what Barney said, Ted could've left but didn't. Even though Barney hasn't been in a long term realtionship, does know something about them. Also Robin didn't seem to mind too much that Ted was out with Barney on the first night out.
Another funny part is when Lilly and Marshall tried cope without Ted. A great scene was when Marshall and Lilly were naked. It was not just for the obvious reason. Even though Lilly and Marshall had difficulties without Ted, I don't think that it tested their realtionship.
This was a great episode that further set up what would happen the season 2 finale.