We Catholics know and understand that this "manna" is the Eucharist, the body, blood, soul, and divinity of our Lord Jesus Christ. Knowing this, it is still extremely easy to receive the Eucharist nonchalantly, without much thought. It is then that we begin to drift towards a state similar to our reading in Acts 7: "You stiff-necked people, uncircumcised in heart and ears, you always resist the Holy Spirit. As your fathers did, so do you." We begin to "do what is right in our own eyes."
Why are we baptized? Why are we confirmed? Why do we go to confession? Why do we receive the Eucharist? If our only desire is to escape hell, well, that very well may be where we will find ourselves. Jesus did not become incarnate, undergo His passion and crucifixion just for us "to not go to hell." No, He did everything in order that we may be like Him. He took on our humanity so that we may take on His divinity--at Baptism. In Baptism, we are His very image, without sin. However, due to concupiscience, we look very much like we were before Baptism; but we--usually, very slowly--grow more and more back into the image of Christ--if we consciously desire this, pray for this. This is part of the power we receive in Confirmation.
God pours His grace out upon us, but we must cooperate with that grace. How do we do that? Let me give an example. God gives us patience. We have it; nevertheless, we must exercise it. If we allow ourselves to be impatient, we are not exercising that grace. When we exercise impatience, we can receiving healing and more grace at Confession. Then we try again--and again, and again. Each time, we return to the confessional for more healing. After time, we begin to see more and more patience in ourselves. We cannot excuse impatience by saying, "Well, God hasn't given me that grace yet." He has; we just don't exercise it all the time. We cannot expect "quick fixes."
In Baptism, we receive eternal life. "Eternal" is defined as: lasting or existing forever; without end or beginning. One will probably think that that means going to heave and never dying again. In a sense, that is true, but it is more than that. "Eternal life" is what God is. He is life without beginning or end. "Life" is no sin, for sin is death. This "eternal life" is what we receive in Baptism. Is it what we still desire today, at this moment? If it is, then it is a desire to be the image of God our Father, as shown to us by our Lord Jesus Christ, the Begotten Son, and as the Holy Spirit is making us--if we allow Him.
As we receive the Eucharist, we can say a short prayer, "Lord, make me more like You."