When Yeh Mera Deewanapan was conceived by Shankar-Jaikishan, they were in a tizzy whether to give it to Mukeshji or to Talat Mahmood. The arbiter was a coin and the toss' result fell in Mukeshji's favour. Personally, I'm glad it went to Mukesh as I much prefer him over Talat.
My favorite Mukesh song is Husn-e-Jaana Idhar Aa, composed by Naushad. If I remember correctly, Mukesh had hitherto been absent from Naushad's recording room for close to two decades. I wish Naushad had utilised Mukesh a lot more; virtually every song flowing from their association is a gem.
This song sounds pretty straightforward but it's actually a very difficult song to sing. Mukeshji falters slightly a couple of times in the song but his overall singing and the beauty of the composition means one can overlook that (I'll leave it to those of you with a discerning ear to pinpoint where this occurs)..
https://m.youtube.com/watch?v=FVMqLoLEWXs