Answer by Rory Young:
First the short answer:
Understanding and tolerance.
Now the long one:
A lesson on tolerance from Africa.
I am fascinated by the interactions between Central African tribes. Zambia, where I live has seventy two distinct tribes recognized by the government and with their own land and chiefs. They are incredibly tolerant of each other.
Well, actually not. The tribes formalise and "manage" their relationships with each other. They have a fascinating way of doing it. It's called "joking kinship".
It works something like this. Two tribes went to war, raided each others cattle and daughters for a few centuries, and then one day everyone decided enough is enough. For whatever reason. Let's say for argument's sake another bigger tribe is moving in and they need to team up. It doesn't really matter why.
The chiefs and their indunas meet each other and declare "cousinship". This means the two tribes are kin in every way, enjoying the benefits and disadvantages of being from the same tribe. Except for one thing. Joking.
Joking means your are allowed to, nay, you are strongly encouraged to tear the ring out of each others' tribes at each and every opportunity.
Here is how it works. I, a "muzungu" (white man) go to the Simwatachela chiefdom (tonga) which has adopted me and I am treated with respect and accorded all courtesies and hospitality as a member of the tribe. Everyone will completely ignore anything different about me, such as the fact that I am quite obviously white. To joke about this would be taboo except for a few people related in a particular way. Simple.
Now, I, the muzungu, go to a Lozi (Barotse) chiefdom. The Lozis are "joking cousins" of the Tongas. I am afforded every hospitality and treated as a member of the tribe. Except for one thing. I am mocked mercilessly.
How can these stupid Tongas think a white man is one of them? (never mind that they themselves also "adopt") Are they completely blind? Is it an attempt to breed new stock? Did the women do it because the men are even uglier than muzungus?
Seriously, anything goes. (If you would like to see a good example of this have a look at the extremely popular Facebook pagespecially setup to enable good, thorough insulting.)
Pretending everybody was the same would be completely idiotic. The two tribes couldn't be more different.
For example, if you visit the Tongas as a stranger, they will treat you as a friend until you show yourself to be a threat/problem/plonker and then they will chase you off. On the other hand, visit the Lozis as a stranger and you be treated appallingly until you have proven yourself not to be a threat/problem/plonker.
In the eyes of the Tongas, the Lozis are rude. In the eyes of the Lozis, the Tongas are false. The way both parties view it, the stupidest thing of all would be to deny that their different habits and cultures are each annoying to the other when in fact they clearly are.
Simplistic or realistic? I don't for one second expect this to somehow be translated to Jerusalem or Kosovo. Such a system has taken millennia no doubt to evolve in this part of Africa. However, there are some things that can be learned.
Different cultures do rub each other up the wrong way. What is the point in denying it? The answer is for these different cultures to find common ground and understand the differences.
For example, in most Central African cultures it is rude to stand up when someone enters the room. In European culture it is rude for men to stay seated. If the two cultures do not know this about each other there could be misunderstanding. The different tribes would get around this (if they are "cousin tribes") by pointing out the differences and teasing each other. The teasing allows them to point out each others differences without causing offence. The next time both would know how to avoid being perceived as rude by the other party.
At the very least people can understand different cultures by learning about them, and by accepting and making allowances for those differences.
This starts by knowing what makes them different.
I remember as a child other white kids laughing at black kids who would stick their finger in their nose as a polite way of indicating they were thinking/considering an answer to a question asked by an older/senior person. The same black kids would be embarrassed if someone scratched their head to indicate they were thinking. As far as they would be concerned it would indicate a case of bad lice or worse!
As for race, this doesn't require explaining or understanding. The colour of a person's skin is not a cultural thing and does not indicate any possible understandable cultural differences that one should try to understand.