I'm sure you can think of a few people in your life right now that are pretty…complicated. It seems that everything that they do is a big deal, or they are really picky, stuck up, sensitive, etc. Some people have the personality of being that way. But when you get to know them a little better, you may begin to realize that you aren't as bad as you thought you were about being high-strung.
In life, you meet SO many people and each of them are unique in their own way. Some are good, some are bad, and some are in-between. Each of them makes some sort of impact on what kind of person you will turn into. However, there are usually a select group of people that really make the most impact on how you act and who you turn into is the ones that are pretty 'high maintenance' people.
Some people freak out over the craziest of things like the way you dress determines how much money you have, or something like thinking that somebody is into you when really it is a good intention, nothing romantic. I feel like in this day and age society has filled out minds with all of these expectations that are near impossible for us to achieve. Society thinks that we should all be living these very luxurious lives and that everything is essentially 'all about me'. Anxiety and depression are at an all-time high thanks to these stakes being placed by society. The people that are high maintenance, in my opinion, look down their noses on others, thinking that they are better than those who aren't as pretty, wealthy, or just all-around personality that doesn't acquire to their liking.
It's sad that people have to think in such a materialistic way in order to obtain happiness. Happiness is something you find within yourself, not something you find within material things, or kicking others down in order to feel more superior than others.