Sorting by colours is easy. Sorting left and right are a little tougher. And sorting by sizes is most time-consuming, given that the sizes are listed on the sole of the shoes.
Imagine the shoe have 5 colours, 5 different sizes, and left/right foots.
There are basically 5 x 5 x 2 = 50 different groups.
Intuitively, the less groups there are, the easier it is to sort the shoes. But at the same time, the grouping should not be oversimplified such that each group ends up being a "mixture" that reduces turnaround time of finding a pair of shoe for the customer.
The helpers were pairing left and right of the same color and size before they throw it into one of the big boxes for the group.
And so I had an issue - What was the point of pairing left and right, when all you do after that is throw the shoes into the box? The shoes have no shoelaces, no showbox, basically they can't be "joined" in any way.
Imagine you have 50 left shoes, and 50 right shoes, of the same size and colour, randomly scattered in a box. It does not guarantee that they will be sold as 50 pairs of shoes. You can have the most detailed plan upfront, but when it comes to picking shoes in a chaotic fair by staff, some people might just end up with 2 lefts, or 2 rights.
So whats the point of ensuring an equal number of left and right in the box if someone might still possibly screw it? So I told the helper to ignore left and right, and just sort by the colours and sizes. By reducing the groups by half, he sorted the shoes much faster.
Some problems are solved naturally and easily. You can have 55 left shoes and 45 right shoes. Well, it doesn't matter. Life has a way of sorting out matters, or shoes in this case. With careful picking during actual operations, you will be left with 10 left shoes at the end of the fair.
It doesn't pay to be too micro sometimes. One risk doing unneccassary things, wasting unneccessary time, and wasting energy on the wrong processes.
It pays not to over-plan. Problems are not solved entirely by planning, but by acting accordingly when the event happens.
So aim to go home on time, get more rest, and start thinking with your brain the next day. It will be a productive cycle.