I know there's been one of these threads before, but I just had a moment myself and it reminded me of the thread so I'd like you to share your ridiculousness too.
Mine just now was that I remembered a dessert I used to have as a child (I think it was called chocolate crunch) which I have previously reverse engineered with custard, hot chocolate powder and digestives. But I just realised we don't have any of the ingredients so I cried.
With DD1, I cried when I was on a plane because the woman behind me had her reading light on.
With DD2, I cried watching the introduction to the London Marathon. Watching someone tie their shoe laces tipped me over the edge.
Please share yours to make me feel less ridiculous.