Just as an example though - sometimes even after all this time - I fail spectacularly at guesstimating carbs in stuff. We were away at the weekend with a gang of folk we know and Friday is fish and chips night. Always hard to guesstimate - probably OK-ish with the chips but how many will I actually eat? Ditto the fish - and who knows how thick the batter's going to be? and again will I want all of it, so best underestimate and correct later if I need to. I ate all the fish, all the mushy peas and 3 parts of the chips - it was all rather good, not too thick batter so the fish was lovely too instead of 'soggy' - and most of the chips were good - none was too greasy and I thoroughly enjoyed it all. Hypo all blooming night. It had crossed my mind last week that I thought my basal insulin needed a bit of attention, so I dialled that down in the later evening on Friday. Saturday was Ok-ish except the early morning (6.30 am) hypo, but best ignore that since I had shedloads of Lucozade and biscuits on Friday night, so probably shot up high and then plummeted. So hypo again at 6am on Sunday, aarrghh. So turned basal down from 4am ish for a couple of hours. Out to Sunday lunch carvery and took 3 roasties and some sliced spuds done in cream in the oven - kind of Pommes Dauphinoise style but weren't that nice actually - not much taste at all. Carrots were warm but practically raw - we all complained about them. So guesstimated after eating - and was high all flippin day until the middle of the evening.
I've been absolutely fine all day since we came home though as I haven't eaten anything I had to guess!
A combination of not guesstimating correctly and my basal being wrong made it all worse of course, as normally I can get away with weekends like this without THAT much trouble - just the odd minor correction or an extra biscuit here or there. But when it just decides it isn't going to play nicely, you are fighting a losing battle really, so you simply have to handle it the best you can - then just shrug your shoulders and forget it!