A person who looks on the bright side of things

One word substitute is Optimist.

Sycophant: a person who acts obsequiously towards someone important in order to gain advantage.
Optimist: a person who tends to be hopeful and confident about the future or the success of something.
Cynic: a person who believes that people are motivated purely by self-interest rather than acting for honourable or unselfish reasons.
Pessimist: a person who tends to see the worst aspect of things or believe that the worst will happen.