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:

1. One fire is extinguished by another
2. One pain is lessened by another, worse pain
3. If you're giddy, it helps to spin the other way
4. 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'.