Even after the Notepad poured black paint over the Yellow Puppet's clown painting, someone still appreciated the work the Yellow Puppet put into the ruined picture enough to frame and hang it up in the puppet's living room.
What are the puppet's favorite colors? The Red Puppet likes blue, the Green Puppet favors red, and the Yellow Puppet prefers green. In other words, their favorite colors are each other's hair (or feather) colors.
On one of the photos on the wall, the one representing the past has the three friends outside their house smiling at the camera. They clearly care about each other at least somewhat.
Despite how unsettling and strange Manny's dad, Roy, is, Manny still likes him and considers him a friend.