When Morhpeus offers Neo the red or blue pill, there is symbolism there
that tells us which choice is right, even if we don't understand the difference
between them.
The blue pill is offered in Morpheus' left hand. The left side is used to
represent something that is backwards or weaker (a left-handed compliment).
Blue is symbolic of sleep and dreaming.
The red pill is in the right
hand. The right side represents what is just, good, or proper. Red is
associated with blood, such as the blood of Christ. It is also symbolic of
danger, anger, and Satan, which are things Neo (and Christians) have to deal
with if they choose the Red Pill.