Complicated further by the real Gardner not being nearly as much of a standup guy as the film portrays.
Glurge: A man, who is presented as moral, sees happiness in making money as a stock broker, studies at it with a high potential chance of failure for no money, and is willing to sacrifice his own son's well-being in order to do so. Also, because of this, it comes across as capitalist propaganda justifying the wealth gaps between rich and poor. If you're poor, it's because you didn't work as hard as Gardner did.
Tear Jerker: Be prepared for the overwhelming urge to call your Daddy and tell him how much you love him.
The Woobie: Chris. The sheer struggle he has to endure over the course of the film (OK, some of it was his own fault through investing his life savings in the bone density scanners) is enough to make anyone feel sorry for him, which is made much worse when he and Christopher are left homeless and destitute and Chris hides this as much as possible not just from the people at Dean Witter, but also from Christopher.
Christopher too. For many of the same reasons as his father. He even asks Chris at one point if Linda left because of him, which is enough to make anyone want to hug him. And then there's the scene where he loses his Captain America action figure and Chris shouts at him because they need to get to the homeless shelter.