"Katy Perry sounds better than you"

Ask them if the have a cold?
Compliment them by saying they sound a signer but make sure that singer is terrible

i cackled

Perched for the inevitable mess.

I experience something similar with a game on this site called Platinum Hit. Just add the words "a little", "a bit", "a tad", "slightly" etc. before you say things so that people think you're nice.

"Have you considered the possibility of maybe keeping your day job bitch?"

If they are singing along to a song, I will ask them who sings this song and when they answer, I say then let them sing it and shut up.

If they are singing on their own, I just tell them to shut up.

I don't subject people to my terrible singing so I don't take it from others.

I don't.
If it's a friend & they want to pursue a singing career, i'll just straight up tell them to look for another option.

Say Iggy can sing better than you.
Then laugh and say maybe your up there with her