University changes a lot for you. I'd say the biggest thing, other than living away from home, if you are living out, is making friends. This is hard as it means you have to leave your home friends behind as they do the same thing by spreading their wings. This can mean, through circumstances, that you don't get to see certain people for ages, even lose contact. Not always the case that you didn't wanna keep in contact with them or that you both didn't make the effort. It jus' turns out your not great at being long distance and your only really good at seeing each other in person. So you'll gradually put them to the back of your mind.
Then the holidays come and you're actually both available. And so you arrange to meet on the phone. And you forget how much you missed them, just to hear their voice, you can't believe you've gone so long without talking to them. Hanging out jus' brings back the happiness you used to have from care free days at school. You talk for hours jus' about your life, a great big catch up that your other friends probably wouldn't be interested in. This sounds so gay. But I don't care.
Basically I've missed my friend. After reading this I suggest that if you've got a friend like this call them now, you won't regret it :)