I've had numerous flights lately where I've boarded fairly late on with my soft sided, correctly sized, rucksack only to find the bins either "full" or closed (and "full"). However, much of what's up there is small secondary bags and / or coats inefficiently stowed. Cue dirty looks from some people when you politely ask if coats can be removed so as to comfortably fit your bag, with the coats then squeezed into whatever space remains, or placed on your lap.