Because I travel one hell of a lot with Singapore Airlines I can get into their lounges and associated lounges at most airports. It is a very variable lot.
Perth: Small, good selection of wines
Singapore T2 & T3: both good, T2 better as it has showers
Delhi: Unmentionaable food.
Mumbai: Ditto but worse
Calcutta: Ditto but has free issue 'roaches. Must be the worst airport in India
Seoul: Get put off by having to get past the Hello Kiyyt shiop but good once inside
UK Heathrow T3: Good, about the best thing about T3 which is a horrible place
Shanghai: Need to ask the slumbering help desk staff to find it, not worth the visit, customer service not part of the Chinese identity.