Song makes my toddler cry.

When he was a newborn, I would sing/repeat the first few versus of “My Bonnie Lies Over the Ocean” to my son when soothing him but replace Bonnie with his name. The notes are low and the tempo is slow enough. When he started self soothing, I mostly stopped singing it.

Every time I start to sing it now, he seems to become upset. I thought maybe it was a coincidence, but I tested my theory. At pajama time tonight, I started singing it. Immediate (cute) pout and watery eyes, so I stopped and he was happy again.

Why does this happen? Anyone else’s kid react emotionally to a particular song?