"...when we pray, do we speak from the height of our pride and will, or 'out of the depths' of a humble and contrite heart? He who humbles himself will be exalted; humility is the foundation of prayer." (Catechism of the Catholic Church 2559)
Isn't need the foundation of prayer? I need this or that, so I pray for it. And I either get it, or I don't. The problem with thinking of need as the foundation of prayer is that when I don't get what I think I need, I may start to question the efficacy of prayer and maybe even the existence of the one I'm praying to. Or I may begin to think that God needs persuading. So begins the bargaining. "Lord, give me this, and I'll pray three rosaries a day for a year!" God isn't changed by bargains, so that's a pointless approach. Maybe God can be persuaded to change His mind through sacrifices. "I'll give up sweets and Bingo, if you say Yes to this prayer." Again, we cannot change God's mind. Need isn't enough to ground prayer.
There is a better foundation: humility. Humility is the good habit of acknowledging that we are fundamentally dependent on God for everything we have and are, including our very being. Starting with humility, we immediately recognize that we don't really know what we need. So, we pray in thanksgiving for what we already have and ask for the grace to receive what He has already, always given us. This way we are always open to recognizing His gifts when they arrive. Rather than telling God what we think we need in prayer, we receive what He knows we need with praise and thanksgiving.
For further reading:
• Hans Urs von Balthasar, Prayer. Ignatius Press, 1986.
• Jean Corbon, The Wellspring of Worship. Ignatius Press, 2005.