Jeremiah 45:5 asks an interesting question: "Do you seek great things for yourself?" That verse goes on the say, "Then, don't!" But, the Bible says that "He will grant us the sincere desires of our heart!" So, if I am sincere, and it's from the heart, then it should be open season on getting my stuff". And that is where we probably go wrong.
Colossians 3 states we are to "seek things from above", first and foremost. Are the things we seek a little lower than that? Would it be safer to be more in tune with what God thinks are great things? God considers it pretty great to have a close walk with Him, to trust Him with all of our hearts, and the greatest thing of all-having His Son as our Lord and Savior. God considers obedience, humility, and charity to be great things. It would be pretty safe to say that if we seek the things on "God's great thing" list, we will find ourselves with a pretty great list, ourselves.
So, the truth is what great things we are seeking will be determined by where our hearts are. Our hearts will define what "great" is, and if we are close to God, we can trust He has already test drove them, and they will be the greatest things we can ask for. Selah!