Marley & Me
The saddest movie I've ever seen in my entire life. I've watched it five times and I still cry every time. The last 30 minutes are torture for the eyes and throat.
The movie is incredibly well developed, the characters are very endearing, and we follow their evolution and that of their family, as well as their adorable dog Marley.
It's very human and very funny; it's impossible not to have a good time watching it. The film shows the positive and negative aspects of relationships and life in general.
In short, there's nothing bad to say about this one. It goes by so quickly and is so enjoyable that I'll continue to watch it every year for the rest of my life. I love it.