In the stereo mix of "Please Please Me" John flubs a line going into the chorus after the guitar solo, it stands out like the proverbial dog's. He knows it too, because you can hear in his voice while he's singing the chorus "Come on… come on… please please me…" that he's trying not to laugh.

The mono mix - both the original and the recent remasters - is from a different take, and the flub isn't present. While the mono mix is, in my opinion, sonically superior… I miss the sound of John smiling.