I've never had a day out that's been an unrivalled disaster from end to end, but there have been Moments:
3 year old DS2 pissing himself copiously in the queue for tickets at the Didcot Railway Centre (think small lake around his feet);
Having to designate a Naughty Tree at Marwell Zoo for 4 year old DS1 to sit under and think about his actions, he was being such a little git;
One memorable occasion at a very MC campsite at a chateau in Normandy, where I had unwisely agreed to letting 8 year old DS1 buy a small penknife at the supermarket, to only be used for bushcraft purposes and under strict supervision. He ran ahead as I was unloading the car, and I found him running around with his little cronies waving the knife wildly at them. While I was disarming and bollocking him, 3 year old DS2 calmly dropped his pants and laid a massive turd on the manicured lawn outside the toilets.
Upon arrival at the Capitoline Hill in Rome, 13 year old DS looked at the forum spread out below him and said "Have you brought me all this way to look at a load of old stones?". Which precipitated a 49 year old tantrum 😆
Also, they have both, separately, puked in swimming pools, sparking mass evacuations.