For Sitcom, I'm going to go ahead and pick one of my favourite shows, and my favourite of the category. It has a good mix of zany comedy, smart jokes, long running bits, and does it with heart. The unreliable narrator makes for some fun storytelling opportunities other shows don't give you. Some of it hasn't aged too well, and probably only worked in the first place because Neil Patrick Harris is pure charisma.
How I Met Your Mother
As for the ending: