How does the Mangekyo Sharingan abilities be unique to each person?

Is it based on what the person is most in need of?

Like for Obito, he had trouble getting on time and his MS had ability to teleport...

Itachi and Shisui were strong Genjutsu users and their MS is related to that...

Sasuke wanted revenge and he got MS related to black flames that burn anything....

Sarada wanted to protect Boruto in the moment when everyone turned on him due to memory switch, her MS is some kind of blackhole and control what is affected by its gravity, ideal for keeping something or someone dangerous away from something or someone...

I don't have a clue what Madara's MS abilities or Fugaku's MS abilities are...