Advice For The Young At Heart.

It all comes down to Observers and Analyzers 

If Boy A meets Girl O - Natural fit
If Boy O meets Girl A - Patience will be required but fiery, the love will be
If Boy O meets Girl O - Remember to spice things up in the sack
If Boy A meets Girl A - Someone will be stepping out

Of course... none of this matters if you make your decisions aesthetically.