Set Fire to the Rain by far and it's her worst song at the same time. Hello is getting there too (not as awful but still annoying as hell).

SLY definitely

There's a few artists whose signature hit is a cover but it's definitely not Adele's signature hit anyways. Maybe in the UK though (after SLY), where it was pretty popular.

RITD outsold and outstreed SLY
Why are people voting for the latter (other than the fact it's better)?
Hello will snatch both in time tho

Yeah MYFML sold over a million in the UK
It was huge there.

Rolling in the deep, it's an absolute classic.
it's also the biggest hit of the 2010's and one of the best selling singles of all time both WW and in US.

SLY is close after and Hello is obviously there already in terms of popularity and what the GP knows.
more lowkey, i'd say chasing pavements and hometown glory are really signature songs for her aswell!

SLY. It's the best song of the century.

yeah, first i think of is obviously Whitney.

Someone like you and she performs it best everytime

Someone Like You.

Someone Like You.

Rolling In The Deep

RITD. SLY is a close second.

Honestly at this point all 3 of them.

Hello

RITD in the US.
SLY worldwide.

SLY > Hello > Rolling In The Deep

Someone Like You. Hello could overtake it tho.