Granted 'When your Smiling' isn't a fast paced, or upbeat song, but what club anthems are? You don't hear Old Trafford singing 'Happy' or Stamford Bridge singing 'Hey Ya'
I sing it before the game, not because I much like the song (definitely not in my playlists), but because it does resonate to me in a way of, its some form of closer connection to my club.
We adopted it as our anthem in the 1980's, so there's abit of history there too with the terraces singing it. IMO 'You'll never walk alone is a garbage song', and you can't tell me that's inspiring and upbeat. But Celtic and Liverpool belt it with pride (albeit Liverpool are silent for the rest of the 90) and apparently inspires the players and generates the atmosphere?
Maybe due to the last few seasons, people feel less likely to sing it as there is disconnection between club and fanbase, and the downturn in our fortunes. But literally why not sing along to it? If it got replaced by an upbeat song, would you sing along to that? Unlikely.
Much rather 'When Your Smiling', than 'Hey Jude', or 'Uptown Funk', which has nothing to do with the club at all.