Most are made up and silly.
The only one I've liked was in college I did a "communication style" one. Where it showed a bunch of different like emails, posts, and conversations and asked which you preferred to receive and which you were likely to write.
10 years later I still think about it, cause the goal of the work was to talk about how if you're a certain communication style what to keep in mind with communicating with others. Like tips to not get frustrated with yellows who don't care about facts when sending emails and how to write emails that don't bore and frustrate people if you're blue. (I'm blue green. I can sometimes write long emails)
I thought about it the other day cause a guy was complaining about all these emails that didn't seem to say anything, they were just about feeling good, and he just wanted them to spit it out. Which corresponded to firey red getting mad at green.
So with that context, do you have any that actually had an impact on you?
So they're helpful but they don't work?
Most personality tests will not tell you anything about yourself that you didn't already know, it will not give you any insights into the correct way to live your life or what is going to work for you.
However, it can help you frame things about yourself in a new light or to help you come to understand the way that you work inside of a larger social picture.
So they don't work to tell you who you are, but they help you be who you can be.
The other responder already had some good points, but I will add: not so much directly but yeah, indirectly they can help you especially to relate to other people.
e.g. ~~let's say that you are an extrovert~~ (except this is Lemmy so uh...:-P) let's say that you are an introvert, and wherever you fall on that spectrum, some extrovert sees a confused look on your face and just won't shut the fuq up about the matter - they are relentless too, and you just want to walk away. THEY need to learn that when talking to an introvert, they need to shut the hell up, and allow the other person to digest what has already been said. Repetition, even using different words/scenarios/analogies/etc. makes the matter worse, not better.
While YOU as the introvert here may benefit from knowing that they legit were trying to help - that's how they are, when they get confused, they talk MORE, rather than less (insert Unix CLI pun here:-D). It's just their natural bent, reinforced over time in however they were raised, and not necessarily a bad thing in and of itself, b/c when directed at another fellow extrovert it could be fantastic. This may give you the freedom to say SHUT UP AND LET ME THINK - which ironically the other person, being an extrovert, may likely love how you are thus being so open about your needs.
Either way, it's good to know about this dynamic of how relationships work, across the varying spectrums of the different aspects of personality traits. Knowledge is Power - use it wisely:-).
That is just understanding the different types of personalities, personallity tests claim to detect what type of a personallity a person has, quite different.
The former is very useful, the latter is just plain crap
Usually, unless you happen to be really strong on some aspect. It's like how Google will "find things" - sometimes it does, as it tries to sell crap:-D.