In Lent, it's traditional to give up (or 'fast from') something(s) that we do a lot of and that we find pleasure in. This giving up or fasting is done:

as a discipline for learning self-control, to free our minds from the chase after material things, to tell ourselves 'no' and make it stick;
to identify with Christ's sufferings, and remember what the true pleasures are for followers of Christ;
as an act of sorrow over our wrongdoings and our state of sin.