There are things that are objective, there are things that are subjective, and then there are things that are both.
Things that are objective are stuff like Maths, Science, Programming. It's objectively wrong that 1+1=3. If you code something objectively right, the program works. If you don't, it crashes.
Then there are things that are subjective, like whether someone prefers red or green, apples or oranges. It doesn't really matter either way, it'd be rude to say someone was objectively wrong if they preferred pears.
A topic many treat as objective when it's actually subjective, is the computer war: Mac vs PC. People who support windows do so because it offers the same functionality for a cheaper cost. But some prefer Apple for what they represent: creativity, innovation, simplicity, so much so that they're willing to pay $300-$500 more. And that's frankly fine, but many PC users get especially toxic about condemning Apple users who are willing to pay a premium for branding, which leads to many unproductive, petty arguments that leave both sides bitter.
Then there are things that are both objective and subjective. Artistic mediums: like drawing, writing, creating videos, can be seen to be 50% objective, and 50% subjective.
In writing, it doesn't matter whether you prefer fiction or non-fiction, minimalism or maximalism, the word beautiful or glamorous.
But there are objective elements to great writing that everyone should follow: such as clarity, knowledge of your material, grammar.
There are many people who treat art like it's completely subjective, as an excuse to do whatever they want because they're afraid of being judged. And what happens is they completely neglect learning objective principles, leading to mediocre content.
Personality is also subjective-objective. It doesn't matter if you're introvert or extrovert, more imaginative or pragmatic, more thinking or feeling, Each trait has its pros and cons, neither one can be said to be 'better'.
Society unfortunately, generally considers introverted behavior (like working alone) to be objectively worse, and shove introverts into group projects they're biologically incompetent at doing, preventing them from reaching their fullest potential.
However, there are also personality traits that should be considered objective: like being caring, hopeful, and grateful. These are positive traits everyone should strive for. If you lack these qualities and are selfish, rude and pessimistic, it'll be bad both for yourself and others.
It's the mark of an intelligent person to decide whether something is subjective, objective, or both. It allows you to decide what aspects of your life aren't worth putting effort in, because it doesn't make any difference, and what aspects are actually worth focusing on, proving you the framework to become a better, happier person
Specific: Why we Should be Utilitarian
Related: Values to Save The World