edit: Okay yeah, that needs more context. I don't really miss people in the long-term; I'm about the worst person you could expect a call from, or a letter, or anything like that. My family's lucky if they hear from me once every three months (though in my defense, it's partly because I only ever get voice mail anyway).
But goodbyes? That actual moment of severance (which is definitely much too strong a word here)? Those hurt. When my father and siblings drove home I missed them so much it actually physically hurt; I don't think I've ever missed anyone that much in my life, ever. Four months--four months and I will see them again! But it won't ever be that trip, that moment again.
One of my housemates came to visit for a day, before she flies to Scotland; we finished up our Supernatural-watching during her visit, because we had this SPN/Doctor Who pact going, which is where the aforementioned random rewatch came from. And now, four months! Is that the magic number?
It's a short time; I know it's a short time. And I know that well before then I'll be back to not calling and forgetting to send letters. But right now it just feels impossibly, impossibly long. Okay. Okay. I just had to write that out.
tl;dr I'd stop missing people if they'd just stop leaving.