From the movie trilogy Lord of the Rings. Samwise Gamgee is Frodo's friend who regularly ventures into bouts of cheesy sentimentalism and/or reminiscence. To do so is to act in a samwise manner.
A: Whoa, we almost died in that car accident.
B: Yes we did. It really makes me think about the fragility of life and how important you are to me.
A: Dude, don't get all samwise on me.