My argument is simple. A perfect life is boring. There is nowhere else to go. You lose all motivation for life, and you have no goals. Rich people often purport that they have everything they had ever wanted, a wife, a solid job, a good home, kids. They can easily get a vacation, a fancy car, even donate to charity to solve problems, but they feel everything is too easy. If your life was perfect, then it would ironically be imperfect. Because life itself is filled with imperfection and a crucial part that we adapt to and manage around. Human is about innovation to curb problems and as such easily managing to modify your life to perfection would be akin to playing god and absurd in the end.
And remember, perfect for you does not mean perfect for everyone. If you were to hate your nearby neighbor, who was very talkative and blabbering on about nothing, then a perfect life might include him being quiet. By modifying his genes, or taping his mouth, or some other means, you make him less likely to talk. But you are restricting his freedom of speech, his freedom of life. By trying to make a perfect life for yourself, you arguably make things tough for other people. Remember that, in modern day, for people to enjoy vastly, a lot of times other people have to suffer, because someone has to give the something that makes the person's life incredibly amazing. Lower class give services to higher classes. That's the way life has been. In order for this to work, you would have to balanced EVERYONE's lives. But most humans are selfish and greedy. Given infinite power to make their life "as good as possible", it's hard to say if the corruption wouldn't get to them, and make everyone else suffer merely to make their lives perfect.
In our lives we individually surrender control, in order to learn more about the world. Though we seem fragile, our minds are more innovative and powerful than we think. We learn through our mistakes and the imperfections of our life. They are humbling and worth going through. It's like the Incredibles said, "if everyone's super, nobody is", indeed, if every moment of your life had no flaws, you would begin to stop appreciating it, as it would be very common to you. But without appreciation, wouldn't you ironically end up with a worse life than before?