He has put timelessness into our hearts

"God has made everything appropriate to its time, and has put the timeless into their hearts, without men's ever discovering, from beginning to end, the work which God has done." (Ecclesiastes 3:11)
This text is part of a famous quote from Scriptures that starts with "There is an appointed time for everything". It is only today that I have been struck by this last part. God has an over-all plan, and that is a plan of joy and fullness of life. But this plan is an ongoing work, and we are involved in its construction. The problem is, we often question the whys of certain events and blame everything on God when things seem crazy and absurd.
If God has a plan, where is our freedom? Are we mere puppets in the hands of a great puppeteer? On the other hand, if we are responsible, then what use is it to pray and to ask God for help?
My own personal theory is this: God's plan is a plan of joy, of success, of fullness of life. We all have our part and what we do, what we say, even what we think, have their consequences in the lives of others and in God's plan of joy. But God continues to be present, motivating and inspiring us, so that despite our follies we may decide to cooperate in His plan. Mistakes and follies also have a place in this plan because they bring out the best in people like strength, resilience, kindness, compassion, forgiveness, sacrifice, etc.
Since we are a part of this puzzle, we are "in" and we cannot see the greater picture. What we see pertains only to our lives, or to the lives of those closest to us; and this may overwhelm us or make us despair. But if we just step back for a while and try to see the bigger picture, or just review a past experience, we will be amazed to see how even the most tragic thing can contribute to God's plan of joy.
Lastly, we will never find full joy in this life. God has put "timelessness" into our hearts. There will always be an angst, a sense of incompleteness, a craving for something more. Our hearts are too noble to be content with the created world, yet it is still too small in this life to be the dwelling place of a God who is so Great.