It's best to avoid kissing in public in India, while cappuccinos shouldn't be ordered after breakfast in Italy.
It's always best to do your research before heading overseas — what might seem like harmless fun back home, could be extremely offensive to another culture.
Even if you've dressed appropriately and read up on local laws, there's a chance an obscure faux pas will identify you as a clueless tourist and offend your hosts.
Locals posting on a Quora thread have identified the main things you need to be aware of when visiting their home countries — from avoiding kissing in public in India to not ordering cappuccinos after breakfast in Italy.
Here is a selection of the best advice.
While it's known for its amazing cuisine, beautiful beaches and busy cities, tourists also need to be aware of the country's three cultures — Malay, Chinese and Indian — and the different customs each holds.
Neha Kariyaniya warned those heading to Malaysia for a holiday to never touch anyone's head or pass anything from above the head, as it's considered to be the most sacred body part.
"Do not point forefinger at things," she added. "Instead point a thumb. Pointing a forefinger at anything is considered rude."
With a large, diverse population, India can be a tricky country for travellers at times. Balaji Viswanathan shared some "non-obvious" advice, starting with a warning against kissing in public.
He said: "In some jurisdictions this can get you into jail under 'public obscenity' (a lot of our laws are stuck in the Victorian era). Although the law enforcement cuts some slack if the couple is married, if the couple is unmarried things can get really messy."
He also said to not "touch anything of respect with your feet. If you stomp over a book, national flag, image of a deity etc, you can get into trouble".
When interacting with locals in Indonesia, touch is something you need to be aware of.
Raska Soemantoro told visitors to not be offended if a hug or handshake is rebuffed.
"Indonesians do not like to be touched," he wrote. "The farthest thing you can ever do with an acquaintance/friend is to shake their hands or do a high five. Hugs are fine when you are already very close to them."
Regina Luce added that it's especially impolite to use your left hand when interacting with others.
"Left-handed people are somewhat rare in this part of the world, but if you happen to be one of them and are absolutely uncomfortable using your right hand, giving a little 'excuse me' when you're accidentally/using your left hand should suffice."
It doesn't matter whether you're married or not, it's best to avoid public displays of affection while travelling through Dubai.
Bahaa' Awartany explained the boundaries further.
"Holding hands for a married couple is tolerated but kissing and petting are considered an offence to public decency.
"Public displays of affection, as well as sexual harassment or randomly addressing women in public places is liable to be punished by imprisonment or deportation."
He also warned against taking photographs of people, especially women, without their permission.
Etiquette and respect are very important in Japanese culture and these customs can take some getting used to for tourists.
Engaging in loud conversations on public transport was one thing Quora user Kazmatsune advised against, although he added it was more acceptable in Osaka.
And if you're a picky eater, it's best to avoid making a fuss in restaurants as it's considered impolite.
"While this custom is pretty common in the US and some other countries, to do so in Japan can cause a commotion and many Japanese would consider it as quite 'inconsiderate' or even 'offensive'."
If you're visiting Italy, you'd better forget your usual order at Dominos — you're likely to encounter a derisive response if you ask for chicken or pineapple on a pizza, or even order a cappuccino after breakfast.
"Expect the 'tourists, pfh!' gaze when you order cappuccino during lunch or dinner," warned Marco Brandizi.
"Cappuccino is for breakfast, we can't understand how it is that you keep ingesting milk together with tomato sauce and you haven't yet died of ulcer."
He added: "Similarly, expect to be frowned upon when you cut spaghetti with the knife. We eat them by rolling them around the fork."
If you want to please your Peruvian hosts, avoid criticising the local cuisine.
"Do not criticize Peruvian food [sic]. Seriously, this is maybe the most sacred thing in our country," explained Jonathan Sanchez.
"Do you want to make happy your Peruvian friends? Make a compliment about the food."
When talking to Germans, expect indepth conversations with a lot of analysis.
Andre Hennen warned that you "shouldn't expect easy conversations" — particularly during chats about religion, politics or the environment.
"Yes, there will be words. A lot of them. Everything will be analyzed from almost every angle [sic]. This can be tough. But it's never a personal thing. It's always about the topic."
Judith Meyer reminded travellers that personal space is also very important to Germans.
"Don't stare. You'd appear either uneducated or mentally ill. Then, if you want to make friends with Germans, don't strike up conversations with strangers at a supermarket or the like; that's creepy."
However, the most important advice mentioned by all contributors was to "not do the Nazi salute" under any circumstances — not even as a joke. It's a crime and tourists have been arrested for it before.
While you might think the meaning of a head nod is fairly universal, it doesn't always mean yes.
In Greece, Iran, Turkey and Bulgaria, nodding your head actually means no.
In fact, Daniel Gospodinov advised against even trying: "Avoid responding with a facial move, you'll pretty certainly get it wrong."