WHAT?: Vulcan technique of getting inside someone's head.
PROS: Can find out what your enemies (or troubled allies) are feeling/thinking. Mind melds have also been shown to cure Pa'nar Syndrome, a Vulcan degenerative disease (though that was, for a time, declared incurable by the Vulcan government).
CONS: Can be physically traumatic, as when Spock melded with Valeris in Star Trek IV: The Undiscovered Country. At beginning of the original Star Trek series, mind melds were described as potentially lethal. Star Trek: Enterprise revealed that mind melds can actually transmit Pa'nar Syndrome.
WHAT?: Tuna salad sandwich with cheese (usually American) run under a broiler until the cheese melts.
PROS: Usually served at diners, and who doesn't like diners? Most often served with fries, nature's most perfect food. Surprisingly tasty.
CONS: The thought of hot mayo and cheese together is, quite frankly, disgusting. Approximately 2 gazillion fat calories. Does not reliably allow you to peer into your enemies' heads or cure Pa'nar Syndrome.
WINNER: The tuna melt. Just don't think about hot mayo and cheese.
(Note: Mind meld information gathered from Wikipedia.)