27-year-old sister wants to move into 21-year-old brother's 1 bedroom apartment after her breakup, doesn't understand when he says no: 'The place is really meant for one person'

Living with family is not for the faint of heart. 

You know this if you've ever done it as an adult. It can make you regress in ways that are hard to comprehend. You can be a full-fledged adult most of the time, but the minute you get with your family again, it's like you're 15 years old. You have the same angst and childlike gripes that you once had. This can be a beautiful thing sometimes, and remind us of where we've been. We get to revert to that earlier state, where we had such close ties with our family members that it drove us crazy. But at a certain point, you probably realized you needed out. You needed to create your own type of life, and you wanted to do that on your own. Maybe it took you a while to gather up the funds to do so. And you're so happy that you did. 

Living alone is a huge luxury. If you're the type of person who thrives on your personal space, then living alone is probably what you aspire to do. You love coming home to an empty house, knowing that everything is just the way you like it. Nobody will judge you for eating pancakes for dinner and leftover Thai food for breakfast. You can play Mario Kart until 4 AM and feel no shame about it. You can leave the house as messy or as clean as you'd like. It's your house, and it's your rules.