I think you're referring to the scene where Benvolio tries to cheer Romeo up, as he languishes in his love for Rosaline. Benvolio doesn't so much give characteristics of a young man in love, as offer proverbial remedies for what he sees as a type of illness. These are:
- One fire is extinguished by another
- One pain is lessened by another, worse pain
- If you're giddy, it helps to spin the other way
- One desperate grief is soon cured by suffering a different one.
In short, Benvolio is sceptical of Romeo's love. And Romeo, unsurprisingly, is unimpressed by Benvolio's treating his love wound as if it were a 'broken shin'.