Do you want to take the red pill or the blue pill?
Morpheus contacts Neo just as the machines (posing as sinister 'agents') are trying to keep Neo from finding out any more.
When Morpheus and Neo meet, Morpheus offers Neo two pills. The red pill will answer the question, "What is the Matrix?" (by removing him from it) and the blue pill, simply for life to carry on as before. As Neo reaches for the red pill Morpheus warns Neo, "Remember, all I am offering is the truth. Nothing more." The choice is deeply compelling.
Why is choosing between what you believe you know and an unknown 'real' truth so fascinating?
How could a choice possibly be made?
On one hand, everyone you love and everything that you have built your life upon. On the other, the promise only of truth.