And I think I know why.... Remember in Primary school, we were always taught to return our plates to the respective stalls. Well, this habit stayed on till Secondary school, where some barbarian would just evolve from nowhere, starting to influence people(in a bad way of course). What did they do?? They bended the rules and did not bother to return plates. And somehow along the way, people just follow them!!! Talk about compliance man...
I don't intend to blame anyone, but it's not too late to change your habit!! All it takes is just to clear after you have eaten!! It is also easier for the next group of people who will be using the same place! ITS THAT SIMPLE!
Disclaimer: What ever I have said is through objective assessment, and is not evidence-based.