It seems that there is no greater joy for a cat than to climb into an open box or a bag or sack left somewhere.
These are not games or a desire to have a separate living space. There is an explanation for everything and here is what these two strange habits may be connected with.
1) Thus, the pet really wants to be alone, take cover or hide. In other words, the cat is pretty tired of the atmosphere in the house, and the animal wants to relieve stress in a safe place.
2) Instincts do not leave even pets alone. A cat can jump out of its "house" at people passing by. There is nothing bad in this, it is just the hunter's instinct speaking in it.
3) And the last explanation for these oddities is the desire for comfort. A domestic cat should have its own personal space where it can sleep soundly in complete safety. In addition, it can smell nice there, which is not only pleasant for a cat, but also memorable.
The simplest explanation is the smell. Cats are smart and know how food gets into the house. Maybe the package contained sausages, fresh meat or fish. As they say, you can't coax a cat out of such a package with a kalach.
As for the paper bags, which might not have contained any food at all, the explanation must be sought in the odd behavior associated with a love of cardboard boxes.
In the end, everyone has their weaknesses and they need to be respected.