If you are thinking about dropping Clannad...DON'T!!
When I first started watching this anime I almost dropped it (would have been the biggest mistake of my anime life, no joke). The beginning felt slow, it felt like it was going to take a long time for the story to get anywhere, and other than the leads, I didn't really like the other characters. Also, I thought the robot thing flashbacks were weird. However, it held my interest enough for me to want to go to the next episode every time.
I grew to deeply care about Nagisa, Tomoya, and Fuko to the point where I would laugh, cry, and get angry with them.
When I finished Clannad, I was content with it. Didn't feel like it was anything super special other than the way I sympathized with the leads. Then I watch Clannad After Story (the sequel series)...Oh my goodness. I have no idea how to even begin to describe the depth of feeling After Story possess. Basically, you should only watch Clannad in order to build a relationship with the characters and understand the story enough to move onto After Story. Do NOT just skip to After Story or else you will miss the most important part of this anime, which is the character development.
I promise, by the time you finish Clannad After Story you will regret absolutely nothing (unless you aren't paying attention when you watch it and miss everything).
