One super-annoying thing I hit often: the Contacts app on a Samsung phone suggests autocompletes of phone numbers in the edit/add contact flow. Do I now need to explain to stupid computer that I am entering a new number that it does not yet know, ffs?
I mean, seriously, something deep in the OS just sees "oh a phone number goes here? Let me supply one from Contacts...". It's trying to be smart, but in a completely oblivious and counter productive way. It's been like that for years. Does no one use these apps?