Odo: Nerys – I realize that things may seem bleak at the moment; but there’s always hope.

Kira Nerys: When did you turn into an optimist?

Odo: Must have been that day in front of Quark’s when we kissed for the first time.

Kira Nerys: That was some kiss, wasn’t it?

Odo: Changed my life.

Star Trek: Deep Space Nine, Season 7: Episode 1 – “Image in the Sand”