What exactly does it mean when a person is high-strung/high-maintenance?

here is the Google definitions for high-strung and high maintenance...

high-strung : nervous, excitable, agitated, temperamental, sensitive, unstable

high-maintenance : emotionally needy o prone to over-dramatizing a situation to gain attention

I dont know about high-strung as I never heard it around but I think it means its someone that is hard to take care of and/or please.

Like someone who needs round the clock attention, needs to have perfect hair, perfect nails, specific foods at specific times, all of which to be at a basic satisfied would probably be called high-maintenance because they take a lot of work to please.

Although I may be wrong. Thats just what I took it out to be.