Taking magic mushrooms with ecstacy - the mushrooms cause the taker to trip out, and the ecstacy makes sure they have a good trip.

Sometimes used to try to sort out someone having a bad trip on mushrooms, if there's no hope of bringing them down quickly - giving them half a pill effectively drenches the brain in seratonin, so whatever happens on the trip they're fairly cheerful about it (and because they're so happy, the trip generally turns into a good one).

Not, obviously, that this is necessarily advised (or adviseable) unless the person is compos-mentis enough to realise what's going on, and experienced enough that mixing drugs isn't going to phase them.

When someone thinks they are the main character of their life. Usually comes with a side of individuality complex, quirky style and a self centered point of view.