[Eternal]

Have you been in a relationship before?
People don't fight with their significant others on purpose. Just like no friendship is without its flaws, people will have arguments in relationships too. The problems is its easy to get a little sick of people when you're around them too much. And sometimes we don't always see eye to eye with other people and someone could start getting upset which can lead to fights.
No relationship is perfect; its something that you have to put effort into and work at.
They aren't bullshit either. Dating is so that you can see what kinds of people you work well with and so that you can take time and figure out who you want to spend the rest of your life with. Marriage is a big deal and its not like people enjoy getting divorced, so that's why we date for a long time prior. Its to get to know each other and to have fun spending time together.
You're still very young and honestly relationships tend to not even last at your age. People will mature as you grow older.