Contagion

Infection. No, we're not talking about my cold (which, by the way, I'm feeling worse, and not better, thankyouverymuch!)

Instead, we're talking about baby smiles.

Don't they just kill you? I know that for me, I start giggling and can't stop. It actually makes my stomach muscles ache.

Don't even get me started on baby laughter.

Just about the only thing that even compares, would be one of these:

Admit it. You yawned, didn't you?