Those who are in the flesh cannot please God. – Romans 8:8 (ESV)
Regardless of how well we behave, how closely we follow the rules, and how selflessly we attempt to live our lives, in the flesh it is impossible to please God. And unfortunately, this began long ago… In Genesis 3, Adam and Eve made the decision to disobey God. They knew God, yet they questioned His character, His goodness, and His word. They believed the subtle lie of the serpent, and that disbelief would mark every son and daughter of Adam and Eve from that moment forward. From that moment on, each person has followed in the example of their first parents, and each person has willfully sinned against their Creator God.
Therefore, just as sin came into the world through one man (that man was Adam in Genesis 3) and death through sin, and so death spread to all men because all sinned – Romans 5:12 (ESV) (*italics mine)
As Romans 5 reveals the extent of our sin, Romans 8:8 reveals the result of our sin. No one in the flesh can please God. It is impossible for a sinner to please God to any degree or measure.

So Now What?

Fortunately, this bad news does not have to be the final news.
Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men. For as by the one man’s disobedience the many were made sinners, so by the one man’s obedience the many will be made righteous. Now the law came in to increase the trespass, but where sin increased, grace abounded all the more, so that, as sin reigned in death, grace also might reign through righteousness leading to eternal life through Jesus Christ our Lord. – Romans 5:18-21 (ESV)
Just as sin entered into humanity as the result of the disobedience of Adam, righteousness entered into humanity through the obedience of one man, Jesus Christ. This is the gospel! This is the good news! In other words, Romans 8:8 reminds us that it is impossible to please God, yet the gospel reminds us that God is eternally pleased in His Son. Romans 8:8 reminds us that we are sinners, yet the gospel reminds us that in Christ God is eternally pleased with us because of the perfect obedience of His Son. Romans 8:8 reminds us that we are unable to please our God in our flesh, and the gospel reminds us to stop trying. Jesus is perfect (and we are not), Jesus is righteous (and we are not), and Jesus perfectly pleased the Father (and we cannot.) And now, we are made perfect (because Christ was perfect for us), we are made righteous (because Christ was righteous for us), and we please the Father (because Christ in us). This is the gospel of Christ! Our God is pleased in His Son, His Son purchased us on the Cross, and His Spirit now dwells in us. We are in Christ, and as a result, God is pleased!