A lot of people dislike Clannad because of the over-dramatization and because of the confusing ending. Although I am a MAJOR fan of the show, I do understand what people mean when they give these concerns of the show. However, these concerns MIGHT lie in not knowing the main point of the show.
What is the main meaning of Clannad? The title itself is Irish for family/clan, and the show itself is also a great representation of what family truly is. The show starts off with an adolescent named Tomoya Okazaki who has not been taught or shown what true family really is, and has found life boring because of it. He has friends but he does not see the point of them because he has no real grounds of what friendship is based off of. His only real friends are Sunohara (a loudmouth jerk with no real character) and Kyou (a violent girl) who just add enough to his life for him to keep around but not enough to change his fatalistic feelings.
Thanks to an added perogative of starting a drama club, he now has to find new people to share his life with and starts to realize the closer that you let friends in, the more important that they become. He helps his friends through their problems and they help him change to become a person with an understanding of life. He realizes what friendship truly is and how it is meaningful. If you look at it from the perspective of the viewer, it appears as though he has found his family. In reality, he actually has. He learns that family can be found in friendship. The most amazing part about Clannad though, is that it doesn't stop there. In fact, it completely shifts.
After the drama club has ended, Okazaki still continues adding friends to his family, but this time he has no perogative to do so. Then Graduation occurs. His friends all leave him and he has to start all over. However, this isn't exactly what we see. While he is starting his new family, on two separate occasions he learns that his old family never really leaves him and will continue to be there for the important times. They are always there for him. Then we see the final shift. We see him learning about the strength of a family. We see him and his family go through trials and tribulations that would (and does) make grown men cry. Many people have questioned why we never see his family come and help him to when these terrible things happen (especially in 5 years). But we learn that they did, and in fact it ends up being the oldest and wisest people in his family that finally make him see the real meaning and strength of family. It's strength lies in the fact that it can thrive in pain and even make good things come out of this heartache.
The ending might make a little more sense when you look at it from that perspective. Even though it was terrible and heart wrenching, he once again will have to rely on his family and look to them for the strength that he needs. The truest meaning of family is that they are always there and Clannad shows that very well.
But if that isn't enough of an explanation, than maybe this can persuade you to look at this a different way.
Clannad is a show that is CLEARLY children friendly (it goes way out of its way to be g-rated and shows that love can be expressed without a physically orientated relationship). So, maybe the point of this show and the wacky ending is simply a meta theme to bring families together.
There are plenty of lessons for every age of the family, but this show does not just give lessons. It is an enjoyable show that anybody can watch. Not only that, but the ending gives so much room for theories and different conclusions that it seems outrageous. So if this show was to be watched by a family, there could be as many as 5 or 6 different interpretations of what happened. The show was emotional enough that most people would be open to talk about it, and share their view. Hence families would start talking and spending time with one another, even if for just a little bit. But one of the themes of the show is that the people that you spend time with will become your family. Seems like quite a great way to get families to start talking and becoming... Well... Families again.