I know, it might not be the funniest joke ever but hey, who doesn't like death note jokes
He was so much nicer in that period where he didn't have the memories from the Death Note
Now this is how it should happen! L is just like 'Hey Kira!" and then Light turns and says back "Ya, what?" and then L knows who Kira actually is!
L: The greatest detective at work (Death Note) Yes I am annoyed. Give me some cake!