Wall Mount Door Knob Bumper

I have a door with one of those little pushbutton locks on the knob. This is the door to my office/workspace, and that door opens and closes a lot.

I have no door stop.

One of two infuriating things happens constantly (sometimes both):

1 - The door opens all of the way, and the button is depressed. The next time the door closes, it locks, usually with me on the outside. I then have to track down something to prod the little latch through a tiny hole on the outside of the doorknob.