“Let a man examine himself.” - 1 Cor 11:28
How many times have you thought it? “I wish my husband would help me around the house more. … I wish my wife wouldn't put up such a fuss when I want to go fishing. … I wish my children would act their age. … I wish my parents wouldn't embarrass me in front of my friends. …” Admit it;  we have all wished and even tried to change our loved ones. We think our lives would be simplified and we would be happier if they would just do things our way. We want to blame the problems and unhappiness in our lives on everyone but the one person who can control our actions and reactions … ourselves.
It's easy to blame someone else for everything. It's much more difficult to reflect on our own hearts and acknowledge there are attitudes and thoughts which need changing. Cain could not face his own failings or the jealousy in his heart. His reaction was to kill his brother Abel. If Cain had examined his own heart and acknowledged he needed God's help, his life could have been blessed. Instead, his life was cursed; he became a fugitive and vagabond (Gen 4:6-12).
There are attitudes in our heart we struggle with and can lead us to lash out in anger, as it did Cain. It is difficult to search our hearts and admit we have angry, jealous, vengeful, and deceitful attitudes. We often don't even realize these attitudes are impacting our lives until we are honest with ourselves. It's much easier to blame someone else for our actions. It is easier to 'examine' someone else. “Why do you look at the speck in your brother's eye, but not consider the plank in your own eye? Or how can you say to your brother, 'Let me remove the speck from your eye'; and look, a plank is in your own eye?” (Matt 7:3-4)
We need to face ourselves and acknowledge our faults to Christ. We would find our lives much more peaceful if we would only bring “every thought into captivity to the obedience of Christ” (2 Cor 10:5).