July 2021
One thing that is a tad bit annoying is only able to increase the purchase amount one at a time.
It would be nice to add functionality to drastically increase the amount faster such as
Shift + Left Click to increase in increments of 10
Hold down the Arrow to slowly start increasing and then slowly start increasing the acceleration of which it increases
Having tabs on top that says 1 \ 10 \ 100 which increase accordingly when you press the arrow
There really are a lot of options and this would help greatly especially in things like Discover University robots and Cooking Spicy food.
July 2021
In the same way that when you go to sell a stack of furniture it lets you input a number, I don't see why they didn't do the same with purchases: too many times I've been ordering the max number of items and have to sit there clicking for far too long.