i think I've been happier when I've been more assertive or become such.
like as a kid or teen i wouldn't really stand up for myself. but now as an adult i do and all the more better for it.
like i recall lately, i was taking a long-distance coach to another city in my country. as i was waiting in the queue, the customer service assistance guided everybody else, but not me. it was apparent she was slighting me, so i spoke up and then she felt "obliged" to handle my issue. years ago, i would not have broached it but now i feel fully able to do so.
The subject of assertiveness usually comes up in situations where one has to fend off boundary violations. In that context, assertiveness tactics tend to revolve around ways to say "No" nicely.
Here are links to a couple random articles on assertiveness used for fending off boundary violations:
The Assertiveness Habit | Psychology Today
Speak Up! 18 All-Purpose Assertive Phrases | Psychology Today
On the other hand, there is the type of assertiveness used by good leaders and negotiators. I've seen that kind of assertiveness described as follows: Create a spectrum with Aggressiveness at one extreme and Passiveness at the other, and then Assertiveness becomes the desirable middle ground. In this manner, assertiveness is defined as the ability to express your own opinion while still being open to opposing views.
The assertive person can state his own position well; furthermore, he can also state his opponent's position well and fairly, perhaps even better than his opponent can. The idea is that an assertive person is more open to compromise or even actively seeks a win/win solution rather than seeking a win/lose (Aggressive) or lose/win (Passive) position.
I've also seen "intellectual humility" described the same way: Be able to assert your own position and yet stay open to opposing ideas; and then perhaps seek a win/win solution of some kind (find some way to incorporate or at least credit the positives of the other guys ideas) rather than fighting for a zero-sum win/lose or lose/win solution. As Wiki says on the subject of intellectual humility, "Church and Samuelson further propose that by being open to the viewpoint of others, one positions oneself for growth and learning."
Note that this kind of assertiveness works best on "soft" issues, where there isn't necessarily one right answer, IOW where arguments are more about who is "more right." On those issues, there's a lot of room for compromise and for seeking out win/win solutions if you can set that as your goal.
