I now argue the fact we, my father and I, never had a proper farewell was a big factor. And I am not referring to the fact I wasn't physically present when my father died; I am talking about the lack of closure when he was still in the game.
We often tell one another the obvious, stating that we should tell our parents or other loved ones how much we love them etc. I don't know about your parents, but in my case such an endeavour is pretty hard - borderline impossible - to achieve in a meaningful way beyond the token effort of saying "mother, I love you". How often do opportunities to say such a thing without sounding like or being perceived as an idiot arise?
For a start, I am virtually light years away from my parents, culture wise. I cite my views on religion as the most obvious indication there: they see/saw themselves as Jews and then as Israelis, whereas I refuse to let the accident of birth determine my worldly prospects. I am an atheist, and while I identify with Jewish stuff on many levels, I will never do so on religious grounds; similarly, I am not one for nationalism, considering it and religion a couple of the world's main sources of malaise.
Second, how exactly do I initiate a conversation with my parents? They were never the sort with whom one can hold a meaningful discourse about anything. Add the physical distance between us and things grow worse. I notice the phenomenon with others, too; when we're away from one another we tell ourselves that we will chat when we meet, in the mean time settling for FaceTime/Skype conversations with limited success because the members of the older generations are often less than capable in the technological department. And on the infrequent occasion we do meet face to face, our conversations seem hell bent on sticking to the mundane "how are you today" level.
Charles Stross summed it up well in a recent post of his. The trouble is that we are too different from our parents. It's not like we're working at one frequency and they're at another; the quick turning of history's pages over the past century means they come from the age of the telegraph while we hail to the 802.11ac goddess. We cannot bring ourselves to communicate using morse code, and they have no idea how to set their wifi up (or why they need it in the first place).
The result is communications that mostly misfire. And feelings of missed opportunities. But these are the natural result of the fact that the times, they are a-changin'. I'd argue that if you are lucky enough to not have this friction with your parents, then you're either lucky to have unnaturally progressive parents or an unlucky person stuck in a time that's not yours to have. For the rest of us it's Communication Breakdown.