Real families are complex, composed of different personalities and values. Sometimes they really are able to get along for extended periods of time. Other times, the differences are too pronounced and being flesh and blood isn't enough to make everyone get along or even like each other. Additionally, there are so many divorced families, single families, blended families that the longed for image of Norman Rockwell's tradional family is rapidly fading. Children have to be shared and shunted between households, families, splinter and new mates appear, religious and political beliefs differ and all the while everyone gets exhausted from working so hard to get along.
Some families actually do get along.
But, even in the best of families, there is usually a point where someone has to get away and breathe their own bit of fresh air. The best gatherings are usually those where there is enough space to get away to be by oneself for a while and those that don't tend to go on endlessly for days. At times, a seemingly wonderful event can end with an unexplained hurt feeling or sudden eruption. Someone, usually innocently, says that one word or opinion too many and what had been a wonderful warm sense of eternal bliss flares into overt or covert chaos. If a version of this has happened in your family, don't feel guilty or badly about it.