Regretting something you did or didn't do can eat away at you slowly and painfully. Whether it is something you said or should have said, did or should have done. I know it's cliche but life really is too short, things can change in the blink of an eye so make each moment count. Being away from family and friends or worse not 'being present' when you are there for whatever reason - is it ever really worth it? If it is then you wont (or shouldn't) have regrets.
It's a good time of year to take stock of not only what you have achieved but also the things you could have done differently. There is always a cost and a benefit to what we do and say, sometimes it's obvious and other times we don't figure it out till much later.
Choice is an amazing gift we have at our disposal. Sometimes the choice seems way too hard and we dismiss it as not being choice at all. It doesn't always feel like we have a choice when things like illness or change we haven't asked for is thrust up on us, but we do, even if it is only the choice about how we respond to the situation we find ourselves in.
Regret is a terrible waste of energy so acknowledge what you would like to have done differently and make better choices moving forward. That is far more useful.