I was angry when I walked into the kitchen earlier and saw the bin overflowing

I wrote an angry note saying that I AM NOT CHANGING THE BIN, that there are bin bags in the kitchen drawer and whoever made it overflow should change it themselves.
Philosophical question: at what point does a bin overflow?
Is it when an additional item placed in the bin takes it over the lip of the bin's body?
I would suggest that this is a harsh rule. Rubbish may reach the lip of a bin quite soon, particularly if you are putting items in there that are not properly condensed or squashed. And if the rubbish in the bin reaches the lip, does an additional toffee wrapper constitute the same degree of transgression as, say, a poorly squashed orange tetrapak carton?
Perhaps it is when an additional item placed in the bin causes the bin lid not to open?
This would assume that the bin is a swing lid, and these bins are notoriously rubbish, making this a non-universal definition. I would also suggest that the arc in which the bin lid moves actually prevents the bin from being filled to it's actual capacity. Poor definition.
Is it when an additional item placed in the bin causes the bin lid not to fit?
Dispensing with the requirement for the bin to open, this could be applied to any bin - including swing bins, making it universal, apart from bins without lids. But strictly speaking, even if it were to have a lid that was prevented from fitting by the rubbish, it isn't really overflowing - it's just being pushed to it's functional design limitations.
Is it when an additional item cannot be placed on the existing rubbish without causing it, or another piece of rubbish, to fall onto the floor?
I think we may be on to something here. But what of squashing? One could squash the rubbish down so that it wasn't overflowing, thus extending the lifespan of the rubbish cycle and leaving some other unfortunate soul to place the final rubbish jenga piece...
Is it when both the existing rubbish cannot be squashed down any more, and an additional item cannot be placed without causing it, or another piece of rubbish, to fall onto the floor?
Yes! Yes, this might be it! But I feel that it encourages inappropriate and counter-productive squashing behaviour in people. Inappropriate squashing behaviours are what cause ruptures in the bag. And ruptures in the bag raise the possibility of a severe 'bin juice' breaching incident. Such Chernobyl-like occurrences are bad for everyone. It's bad for the bag, it's bad for the bin and it's bad for the kitchen as a whole... particularly if it drips.
Is it when both the existing rubbish has been optimally squashed, and an additional item cannot be placed without causing it, or another piece of rubbish, to fall onto the floor?
Too difficult to pin down. Modern science has yet to discover a method of determining optimal bin squish.
Is it all subjective and merely a battle of wills as to who can stomach the sight and smell of a rancid bin the least?
Bingo. And putting a sign up to tell people that you won't cave in is a dead give away that beneath your staunch signage policies, you fundamentally care about the bin situation.
You blinked fucker.