My diabetic experience has been pretty similar to @neobrainless‘.
Apart from occasional lapses when I’ve abandoned testing altogether and eaten anything that didn’t moo or move, my HbA1c has been around 7.5. Anything as precise as @Tim‘s, “This meal is 70g carbs, I’m 1u:10g so 7u should cover it…”, seems to belong in the realms of sorcery or science-fiction! My biggest problem is that, living alone, I cook for myself so I always overeat (I’ve overeaten since I was a child, it’s a long story), psychologically I’m almost incapable of throwing food away and supermarket portioning is usually aimed at couples.
Still nobody ever said life was going to be easy did they?