This is very self explanatory, if you read and comprehend the question. One passage speaks negatively about ghosts and the other does not. All my misery vanished is a direct expression that some ghosts are friendly.
Explanation:
"All my misery vanished--for a child might know that no harm could come with that benignant countenance."
"I sat down and fell into a dreamy contemplation of that great footprint in the ashes.
On one level, the mood of "The Veldt" is clearly one of fear and paranoia. We can sense this from the very first lines of the story: "George, I wish you'd look at the nursery."