Answer:
We haven't forgotten yesterday's picnic.
 
        
             
        
        
        
Answer:
 playful and comical
Explanation:
From the excerpt, the mood is  playful and comical.
This is true because the author revealed that they "pattered pitty-pat, pitty-pat each with feet  and toenails, ears and hair, everything but tails,..." This shows that they were in a playful mood. Also, despite the way they pattered, when they got to the Philadelphia union depot, they had nothing to say. This also added a comical effect in the excerpt.