10 Small Details You Only Notice Rewatching How I Met Your Mother
9. Sandwich Time
The characters move around so much in How I Met Your Mother that, at some point in the series, every major character except for Barney has lived in what started out as Ted and Marshall's apartment.
By Season 4, Marshall had moved out, and and it became Ted and Robin's apartment, but by the end of Season 7, both Ted and Robin had found new places, and it became Marshall and Lily's apartment until the penultimate episode.
The apartment has many lively details on its walls across every owner, but one constant yet easy to miss feature makes for a nice joke once you notice it. In every episode, every single clock is set to 4:20, no matter the the time of day. Whether this is just a joke between Ted and Marshall that stuck throughout the series' run or a fun gag by the creators, it's a nice touch to the apartment.
Why 4:20? Probably because of the number's connection to... eating a sandwich.