In many places I've travelled praising a child to it's parents (what a beautiful, smart, tall, funny, clever, fast... ANY praise) is equivalent to swearing at a child in this country. BEYOND rude. Uncalled for. Friendship ending, enemy making, absolutely intolerable. This is one custom I can NEVER keep straight where it's practiced, so I nearly never praise children's attributes, and instead praise their actions, and never to their parents, but directly to them and NOT anything like "beautiful" etc. that they have no control over. Things like "That WAS very fast!" instead of "You ARE very fast!" or (scary rude), "Your child is so fast!" (invites something terrible happening that could make them 'slow' for the rest of their lives, or if your praise beauty, brings on disfiguring accidents, cleverness to head injuries or death, etc.) It's subtle, but it's key.
((I am sometimes rude on purpose, but I NEVER use this type of rudeness on purpose. Saying what a beautiful baby = I hope someone pours acid on your baby's face... and that's just beyond me.))
When I lived in Japan 20+ years ago it was good luck for a pregnant woman to have her photo taken with a blonde person (I was blonde, and in LOTS of photos with pregnant ladies!!!).
Also in Japan, it was considered rude NOT to offer treats to children (taking candy from strangers) if you were around a child for more than a few minutes (uncrowded train, doctors waiting office, standing in a long line at a store, etc. If there is a child there, one is responsible for either giving them something or giving them your attention for a few minutes. On planes, this often means offering to hold the baby / play with the toddler/ etc. Often gets reeeeally misconstrued by americans.
Similarly; horrifically rude to open a 'real' present in front of the giver AND any present given needs to be met with a present of equal value. (Borrowing is also something of a foreign concept. If you 'loan' something, expect to never get it back, but to recieve something of equal value in return at some point in the near future. The ONLY exception to this 'rule' being 'going away' presents; which need to equal how much the person leaving has meant to you in your life while they were there. When we left, we were given 10's of thousands of dollars worth of presents. We never would have gotten these things while we still lived there (because then we would have had to have reciprocated).
I LOVE LOVE LOVE the Japanese tradition of mom eating seperately from the family, after the family has eaten. I didn't get it as a kid. As a 4 meals a day cook as a wife/mother... I JUST WANTED TO SIT DOWN TO SOME PEACE AND QUIET. The few times I could serve my family, and then go read a book/ take a shower/ have some personal time and THEN eat were pure bliss. Oy. It's viewed as a 'subjugating' concept here in the US, but sakes alive, after spending an hour cooking and sweating the LAST thing I wanted to do was then immediately sit down all in a mess and eat/ enforce table manners/hold any kind of conversation. Ugh. No thanks! ((I modified this tradition to that I'd finish cooking, have everything set on 'warm', and then go take a 10-15 minute break to refresh. <grin> Still do!))
In traditional Bali, children aren't set down until their 2nd birthday in some areas, and feet are not allowed to touch the ground for 6 months in other areas. This includes while sleeping most of the time.
In southern Italy (can't speak for the north) NO ONE sees someone shocking (purple hair, etc.), attractive, smelly, interesting, etc. and turns to their friend. INSTEAD they tell the person themselves. LOVE this cultural tradition. Que Bello! Que Bella! can be heard in ANY crowded place hundreds of times. Along with all sorts of "Captian Obvious" type comments. It's this lovely constant flow of information.
Along the Mediterranean (EU, ME, N.Af, etc.) it's traditional to pick "your" beggar. Part of why westerners get "overwhelmed" by beggars is that they don't know this tradition. They'll usually give you their name, and as people approach you, you just say their name (or the intersection) and the hordes move onto someone who hasn't "picked" their beggar, yet! When living/travelling in those areas, I make sure to meet up with "my" beggar every morning on my way out, and spend a minute or two with them on my way back home for the last time at the end of the night. (AKA pick someone close to where you're staying. Word travels quickly when you're consistant, and you only need to ID that you're taken when you're quite far away. I usually give cigarettes in the morning and some food or change at night.