Manners are funny things. What one person deems rude might be fine to another, and what used to be considered the norm nowadays is probably all but extinct.
For example, 'a gentleman should always remove his hat when he enters a room' comes down to what kind of room he's entering. 'Elbows off the table' is rarely abided by and 'children should be seen and not heard' does not apply.
Add social media to the mix and you've got a whole new world of rules and unspoken etiquette. To wade through the rules and regulations of modern manners we enlisted the help of David Meagher, a manners expert who has just written a book on the very topic.
First scenario on the list? Umbrellas. Why do so few people know how to walk down the street holding an umbrella when it is raining?
"You need to watch out for other people when you use an umbrella and if you're a tall person then lifting yours up to let someone pass is the polite thing to do," Meagher told The Huffington Post Australia.
"If you're walking in the rain with an umbrella and you suddenly find yourself under an awning then you should put your umbrella down while you're under cover. And never shake out your umbrella in a crowded area -- umbrellas are for keeping people dry, not making others wet."
Next up, the age old question of who should go first. Should men still be expected to hold doors and let women go first?
"I like to be gender blind when it comes to things like doors and elevators and let whoever is in the lift with me get out first."
"Sometimes, especially if you're in the lift with a man, that can lead to a whole lot of back and forth with 'you first', 'no, you first'. If that happens I just say thank you and get out of the lift. If it's a crowded lift then the people closest to the door should get out first to make it easier for everyone else," Meagher said.
Another area of contention is flying, planes and airports in general.
"Plane travel can be stressful at the best of times and I think if everyone just followed the rules it would be a more pleasant experience for everyone. That means only taking the approved amount of hand luggage (and not hogging the overhead lockers)."
"Only board the aircraft when you are instructed to (if, for example, boarding is going to be by row numbers). Don't ignore your child if he or she is kicking the seat in front of them. And look out for the person in the middle seat -- no one likes sitting in that seat so, don't make it worse by hogging their armrest," Meagher said.
"A lot of people get worked up about the person in front of them reclining their seat, but that's what the seats are designed to do. Having said that, you should be aware of what the person behind you is doing and maybe wait until they have finished eating before you recline back. And as far as thongs on the aeroplane go, my personal opinion is they are best reserved for wearing to and from the beach."
Ah, social media. Just read the comments sections to find some of the most opinionated people on earth. So, where's the line between freedom of speech and being a dickhead?
"It's really easy to unintentionally start an argument on Facebook and a lot of the time it's simply because someone misconstrued someone else's comment."
"It's always a good idea to be clear and concise in your comments and emojis can really help you set the tone of what you're saying. If you really disagree with something someone has posted then by all means say so, but do it in a thoughtful way rather than an aggressive way," Meagher said.
It's important to know the difference between a debate and an argument.
"There's nothing wrong with healthy debate and social media is a great place to conduct intelligent debate between people. If it becomes offensive or aggressive then I would either take the discussion offline or block the person and delete their comments if it's really bad (but be warned: that can aggravate people even more)."
"If you just can't help yourself and you want to post what might be taken as a negative comment on someone's Facebook or Instagram it's a good idea to set yourself a cooling off period before you actually click post," Meagher said.
Lastly, as for those annoying over-posters?
"I think there is such a thing as oversharing on social media. Personally, I don't want to see my own dental work being done, much less someone else's."
"And while it's nice to see what people are up to on their holidays there can be a fine line between delighting people with your Instagram holidays posts and boring them senseless (and making them jealous). A good rule of thumb is to confine yourself to three posts per day," Meagher said.
David Meagher is the author of The A to Z of Modern Manners, published by Vintage, $24.99
Click below to follow HuffPost Australia on Snapchat!Suggest a correction