Asking : "What do you think about my new pencil case?"
"I think its very nice"

Giving : "I think you should cut your hair"
"I think so"
A: What do you think about the musical Phantom of the Opera?
B: It has a good music, amazing actors and a nice plot, but I'm not really interested with the romance on it.
A: Oh, so what's your opinion on some romantic movies?
B: Romantic movies are cliche and sometimes full of nonsense.