The friends you made in your hometown are the ones that know you better than anyone else and will ultimately be there for you through everything.
First, they went through what we all know as the dreaded 'awkward phase' with you. They didn't judge you for your braces, acne, and raging hormones because it was happening to them too.
Second, you guys can also talk about how much you miss being together in high school. Regardless of whether high school was the best or worst time in your life, there's no doubt that you loved being with your friends.
Third, they are the reason you're excited to come home during breaks. The friends that you make at work or college are great, but reuniting with the crew is probably one of the best feelings ever.
Fourth, throw backs. They know every embarrassing moment you had in high school and still make fun of you for it until this day (and vice versa). You can have conversations for hours solely about the dumb things each of you have done. Most likely, you have an album of all their ugly selfies and embarrassing pictures.
Fifth, you're just as close to your friends' family as you are to them. Their parents and siblings know you from all the times you went over to their house and probably ask how you are from time to time.
Sixth, you still gossip about other people from your high school. Yes, that time in your life is over but it's still fun to talk about. What ever happened to that kid who never showed up to class? Or those kids that tried to be Instagram famous?
Seven, along with the gossiping, you hate the same people and it's awesome. You can always count on your friends to send you Twitter/Facebook screenshots saying "OH MY GOD SHE'S SO ANNOYING RIGHT?!"
All in all, it's just easier to relate to your friends from home. They accept you for all your flaws. You guys could go months without talking and go back to talking like best friends. They understand things that other people just wouldn't.
I love you guys!