This phenomenon is primarly driven by scarcity - you share a large bowl when you eat because you cannot afford for everyone to have their own plate. You share chairs because few can (or choose to) afford to have more than a couple chairs of their own.
In the west we are capable of having our own and are even frowned upon when we don't - millions of garages and closets across the west are filled with tools, toys, clothes and sports equipment that are barely used once a year (or once). You wouldn't dare share the same cup with all your co-workers or all the people in line at Starbucks - of course not! This is what cups, cans and bottles you use once and throw away are for.
Finally, if you decided to gather enough courage to knock on your neighbour's door (at random) to talk to them, you definitely wouldn't ask them to borrow you a bucket everytime you need to flush your toilet because you do want to pay to fix its flushing mechanism.
However, there is one thing I have noted in my African experience that is not easily shared. It is work.
Realizing it has surprised me as I only was able to make the connection recently. This is probably because the thing most often shared in the west is work. I have grown up in home not unlike many others where work was shared. People cooperated to see the benefit of the whole entity. Leadership pulls people together to get people to share in a vision and work towards it. (You may disagree but I see the progress of our culture has been entirely dependent on it)
It is possible that it is related back to the lack of affluence. However, I would have thought it would drive people to group together to help overcome. Instead, there seems to be more of a mistrust or worry about who will get the best of who. Perhaps the stakes always seem high even with small value - you can live a week off of $3 here. In addition there are very few controls and reports in a cash society. For these reasons I can see it hard to trust people.
In many cases you can ask the question if the affluence is cause or the symptom of not being able to work together.
A few examples:
The power bill... People would prefer paying for a $60 meter so they can differentiate who is consuming exactly what and avoid paying a flat rate (a the full power bill for the average family is $3 or less - the differences would be a dime or two)
Farmers here do not have a co-op to help sell their crops at a fair price. Each farmer would rather each negotiate their own price. (I guess for either believing they can do better, lack of trust or or not having to pay a communal due or membership fee) They later complain when the get a bad deal from the savy businessmen who waits until they are starving before offering to buy it at an under valued price. .
Husbands and wives often refuse to share in each other's responsibilities (this is particularly true of men) - even if there are coinciding responsibilities, a sickness or a birth. If something isn't right or working (dinner is late, daily market money not being enough). When such an event occurs there is little collaboration on how things should be resolved or improved upon.
Women and men will seldom collaborate on business ideas or ventures. This is true even when it could make the difference between starving and eating or there is no or little downside the offer.
Each person wants their own business and to be accountable to themselves alone. I have seen this in cases where someone (me or others) have even offered an amazing deal. Like offering paying all startup cost or buying communal tools to be shared)
What triggered today's thought is I am currently trying to get a group to collaborate in synergistic businesses to provide pull through revenue opportunities. ie. Sew a young women a custom made dress - why not sell them the custom made bracelet, necklace and earing that go with it? It just seems like a slam dunk but everyone is more worried about being compensated for their exact work and costs. Argh!
All said, if I see progress in working together before coming home I will be quite pleased. :)