The Feeling of emptying a glass
Why does a container of any fluid, always seems to spend more time feeling empty than it does feeling full? There may be psychological reasons, but, there is a purely tangible reason too.
We can easily tell how much fluid is in a typical container by the 'feel' based on it's centre of gravity. Assuming a central hold on the flask, a full container has a higher centre of gravity, and as a result, is less stable. It's this stability (Or lack of) that gives us the feeling of 'fullness', or 'perceived weight'
The 'perceived weight' changes much more rapidly when the centre of gravity is higher, and changes far more subtly towards the bottom of the container. Exactly the same amount of fluid lost twice over will feel like less the second time, so, assuming a consistent flow over time, it will spend more time feeling empty than full.
Don't Believe me? Try it at home. Any comments or flames, just /msg me