3 is best! there isn’t much continuity between eps so you could just watch the ones i listed (nb. kicking bishop brennan is part 2 of a two-parter). i can’t think of any particular reason to watch them all in order, although the consistency level is pretty high so i’m not saying you shouldn’t either. my top 3 in particular are masterful examples of tight comic construction from beginning to end, they’re essential viewing for anyone who likes comedy IMO. a lot of people would pick ‘song for europe’ as well, that’s a very beloved ep that was tough to leave out.
i love that show in general. great sense of place, you really feel stuck on a remote island with these people, there’s something melancholy and wintery to it. love the surreal/absurd touches, the range of great side-characters, the way it constantly pokes fun at religion without ever feeling like it’s taking cheap shots. some of the jokes are a bit too broad or slapstick but that doesn’t hurt it much for me. i’d take it over every british sitcom aside from maybe peep show.