Add a character or choose an existing character with a crush on another character. Have them slow things down and/or interrupt the plot to try and get some one-on-one time with their crush. Just having them come up with good reasons for this to happen gives you more dialogue. For added exciting conflict, have other characters realise what is going on – they disapprove and block all attempts.

If you want irony, have the crush in question trying to do the same thing.

For creepy, have the crush want nothing whatsoever to do with the character.

If you want comedy, have the crush oblivious and have fate (or plot) provide endless frustrating preventions.