Prayer isn’t just asking for things. Prayer is praising God, thanking Him for all He has already done, talking to Him about what’s going on in our lives, sharing our dreams and our worries, just like we would with anyone we love. You can’t have a relationship with someone if you don’t talk with them.
God has also given us free will. We can believe in Him and talk with Him, or choose not to. God has also given us the gift of His Infinite Mercy, but He doesn’t force it on anyone, we have to ask for it (which is why I love the Chaplet of Divine Mercy prayer!). There are so many blessings God is waiting to shower on us, but we have to ask for them, too, and always that everything be done according to His will (meaning what’s best for our salvation).
God has an abundance of grace waiting for us. It’s like He has to hold the gates shut to keep it from bursting out. When we pray, He opens the floodgates and showers us with grace, mercy, and love!