Harry watched, amazed, as a portly ghost approached the table, crouched low, and walked through it, his mouth held wide so that it passed through one of the stinking salmon.
"Can you taste it if you walk through it?" Harry asked him.
"Almost," said the ghost sadly, and he drifted away.
"I expect they've let it rot to give it a stronger flavor," said Hermione knowledgeably, pinching her nose and leaning closer to look at the putrid haggis. (8.93-96)
One of the most notable things about the ghosts in Book 2 is how human they choose to be. Nick is hurt and angry that Sir Patrick won't let him join the Headless Hunt, and here we have this fat ghost who misses food so much that he tries to taste salmon by drifting through an empty plate of it. So it comes down to sports and food. These ghosts may have died, but they still want to play and eat the way they did when they were alive. If you were a ghost, would you try to continue your human life? Would you do something else?
