It's wrong to ruin something someone else enjoys for them.
Frasier just finished watching the new hit movie and is talking to a friend who hasn't seen it but wants to.
Frasier wants to talk about the movie.
Fraiser expresses to his friend how much he enjoyed the movie but avoids spoiling the plot so his friend can see it for themself.
Fraiser spoils all the twists and turns of the movie to his friend.
Fraiser's friend becomes even more excited to see the movie.
Fraiser's friend is upset by the spoilers because they enjoy watching movies without them.