input: Generate a short movie review that has "negative" sentiment.

output: lacks balance ...

input: Generate a short movie review that has "positive" sentiment.

output: thought-provoking

input: Generate a short movie review that has "negative" sentiment.

output: watching the proverbial paint dry would be a welcome improvement

input: Generate a short movie review that has "positive" sentiment.

output:
( unintentionally ) funniest moments