The Havamal is a poem that provides a number of good social mores for anyone who wants to read them and live by them. However good social mores are not available today. Indeed many of today's social mores are basically shit. Stand in line, hold the door open, wait your turn, give the other person the benefit of the doubt, help the peoples that insult your kin and rob them.
In short today's social mores are used to stymy and take advantage of Nice Guys, who are treated as chumps. One of the those is that men are expected to 'Man Up' and marry sluts who have pissed away their most 'Biologically fertile' and productive years (20-30), but men are not allowed to piss away their most 'Economically fertile' and productive years (30-40). Social mores like this and others are used against Nice Guys, often by the antipode of the Nice Guy - the Nasty Girl - who knows these mores and uses her legalist mindset to try and exploit them to her own advantage.
With that in mind here is a list of how the Nice Guy is expected to behave in everyday life:
The Nice Guy is expected to..
...be tolerant of the stupidity of others.
...be patient of females who are incompetent at something (the tacit reason for tolerating incompetence is because women have supposedly been 'subordinated' by the 'evil patriarchy' for the last N+1 thousand year, thus you must allow them to make mistakes).
...speak truthfully, even if it's about things that others would mock in you; whilst others are allowed to lie as much as they want.
...never defend yourself from physical or psychical/mental abuse (e.g. 'never hit a woman', 'turn the other cheek' - even though Jesus used a whip once and called Pharisees whited sepulchres).
...give other people the benefit of the doubt because 'you' are the one who 'might' be wrong. (Women often use this as a weak form of defence against any claims that you make about anything: they stand there with their hands on their hips and say "Well you might be wrong mightn't you." Intelligence Agencies use a variation of the tactic and call it 'Plausible Deniability').
...defer to the judgement of the other person if you both disagree on a common point, because it's polite.
...try to help other people (even if they have no intention of returning the favour), to such an extent that the Nice Guy loses out because of it.
...treat the ego of the other person carefully i.e. not puncture any delusions of themselves or beliefs that are wrong; and the Nice Guy must do this despite the maltreatment that they receive from the other person.
...never appeal to authority figures (e.g. academics, social paragons, experts) even though the other person can do it all the time (e.g. atheists who defer to the views of 'Scientists' despite the fact that they themselves have never been in a lab since high school).
...play by the rules of the game, even if the other person decides to bend or break the rules (e.g. playing chess with a person who thinks its 'fun', 'naughty' or 'cute' to start playing by the rules of Checkers/Draughts when the Nice Guy is winning.)
All of these (and probably more) are rules which Nice Guys are stymied by day-in day-out. And what's more is that the other people, those who wilfully knowingly exploit the Nice Guy, always have some shield that they can run behind and defend themselves: the first shield is social conventions (friends, family, co-workers or anyone that can form a 'mob' to browbeat the Nice Guy); the second is civil laws (the police and judiciary).
Both of these shields are used to prevent the Nice Guy from using the only weapon that he can to discipline the 'other people' effectively. And what is that weapon? Violence. Violence and physical aggression (anything from a loud voice and imposing body language to actual Physical Force - lbs/ft or Newton Metres - from body parts or tools.
So what's the answer to being a Nice Guy and abiding by these BS social mores that conspire to screw you over time after time? Abide by social mores that work for you rather than against you. Me? I'm trying to learn the Havamal and hopefully it will (or is) yield/ing positive results; it might work for you, or you might use another guide instead. Whatever it is, use social mores that work for you rather than against you. Zero-sum social mores don't produce productive societies.
A man must be a friend to his friend,
and give gift for gift.
Men should use mockery in return for mockery,
and deception in return for a lie.
Havamal, Stanza 42(http://www.beyondweird.com/high-one.html)