The bathroom incident
Son walks in while I'm in the shower and asks 'Dad why do you close the curtain?' I tell him 'So you don't see me naked.' He thinks for a second and goes 'But I already know what you look like, you look like a big hot dog.' I'm never recovering from this.
This is gold. My son walked in on me the other day and asked if I was taking a bath with my clothes on. The logic of a 3 year old is something else.