Thanks for the explanation! I completely understand the workarounds due to the lack of time :D I think you managed to prioritize well.
Yes, I think you are right. My confusion probably comes from the fact that the click logic is not necessarily always the same. For example, when you take out the coffee from the machine, I would expect a left click for "pick up", as in other spots. But this can be polished/explained in a later patch easily.
It can also partly be because as I am grabbing things from one spot to another, sometimes the game randomly refuses to accept the input. Example: if you take a freshly brewed cup of coffee, sometimes you can easily to give it to the customer right away, but sometimes you have to drop it first and try to give it again.
By "overlapping interactables behaving in a weird manner" I mean the following:
If you are putting a cup in the machine as a guest is leaving in the background, the cup falls of the machine towards the left edge of the screen, and starts weirdly vibrating. This sometimes occurs randomly too, but I found that it almost always happens if there is a person behind the machine.
If you are reloading the machine while an empty cup is in there (nothing is brewing, since the machine is empty), sometimes the bag of beans bounces off/slides off/is placed on top of the machine while still being full, and you have to try again.
A similar thing happens with the bin. Sometimes the item just falls down on top of the stack of cups, and I have to grab it from the air.
Sometimes when you add milk/chocolate to the coffee, it just "stacks" instead of combining.
Have a great day! And be proud, you created an awesome game! :)