In just three days we will be in the Lenten season. We begin each Lent with Ash Wednesday as a reminder that we are dust and to dust we shall return (Gen. 3:19). It is good for everyone to consider this truth because we will all have to face death sooner or later. So many are attached to the things that will deteriorate by decay or rust. Money, power, entertainment and simply doing nothing occupy the time of people in the world.
God wants all of us to be with Him in this life because He loves us. It is the best thing for us. He wants us to abandon sin which makes us unhappy slaves. We cannot serve two masters. We must love God with our whole heart, mind, strength and soul. To do so involves saying "no" to all sinful temptations and even to some legitimate desires. This is not easy because there is a barrage of temptations from the world all around us. Moreover, the devil comes into the scene and tempts us, as well as our past sins. That is why it is important to go to sacramental Confession frequently and to make reparation for forgiven past sins by prayers and charitable deeds.
The reason why it is good sometimes to deny ourselves good things is that it helps us to focus more upon God. Everyone sees the wisdom in this to some extent. People see diet and exercise as valuable for a healthy life here. Mortification or self-denial is good for a healthy spiritual life here and in the next world, Heaven. St. Francis de Sales said that self-denial "...strengthens our spirit as it mortifies our flesh and sensuality. It raises our souls to God. It gets rid of concupiscence by giving us the strength to overcome and mortify our passions, and it disposes our heart that it may seek for nothing except to please God in everything." (from his Sermon on Fasting).
Because it is a difficult task to lead an authentically spiritual life, some seek an easy religion. There is the religion of the upwardly mobile: succeed in this life and be religious too. There is the heresy of making excuses for whatever we would like to do: God wants me to be happy so it's OK to indulge as long as I don't hurt anyone. But, in reality, with this attitude we hurt ourselves. The soul becomes dull and dead to the Life of God.
During Lent, we have the opportunity to draw up a plan of mortification for each day. This along with our prayers will enable us to know God's Life and Love.