That's just down right rude. Well, that game has carried over into adulthood. When attempting to use an elevator, do not block the doorway. People know that there will be other people waiting to get off the elevator and yet they insist upon standing right smack in the middle of the doorway. No, I'll go left you, go right.
Nothing moves people faster than a sticky, whining toddler strapped into a quick moving stroller.
Chivalry is not dead. Little lady pushing big stroller. Big lady pushing little stroller. At the very least, smile at her. She's just being friendly.