1) When a born again believer sins, he can be sure he will reap what he sows (Gal. 6:7-8). If we get caught speeding, we will pay, literally. God may forgive confessed sin, but the courts of man seldom do. With unconfessed sin, the believer can be sure his Father will not ignore his iniquity (Heb. 12:5-11). If the Lord does not respond with correction when you sin, then the passage from Hebrews says that you are not God's child!
2) Because all men sin, the actions of others often effects those around them (Rom. 3:23). Some examples of how the sins of others effects believers, Jesus was crucified by sinners (Mt. 27:25). Abel (Gen. 4:8), John (the Baptizer - Mk. 6:22-29), Stephen (Acts 7:59), James (Acts 12:2), and eventually all the Apostles but John were martyred as a result of the sin of others.
3) Satan is constantly looking for opportunities to mess with mankind, especially with God's children (Job 1:7; 2:2; Eph. 6:12; 1 Pet. 5:8; Rev. 12:9). Jesus described him as a thief bent on stealing, killing, and destroying (Jn. 10:10).
4) Because of the fall of Adam, our planet was cursed by God (Gen. 3:17-18). The Apostle Paul described the result of that curse this way, "For we know that the whole creation groaneth and travaileth in pain together until now" (Rom. 8:22). Today, our planet is constantly visited by earthquakes, hurricanes, tornados, floods, drought, disease, and death.
5) We know God is Omniscient (Ps. 139:2), Omnipotent (Rev. 19:6), and Omnipresent (Jer. 23:23-24), and yet, believers still suffer. But, we also know that all that He allows to effect our lives, is motivated by the love of God (Jn. 3:16; Rom. 8:28-29; Heb. 12:6; 1 Jn. 4:8). Absolutely no harm can come upon man unless God permits it, and He only permits it to bring about good. The ultimate example is when Jesus told Pilate, "Thou couldest have no power at all against Me, except it were given thee from above" (Jn. 19:11). Because God allowed Pilate to crucify Jesus, our sins have been forgiven! That's definitely good!
There is peace in knowing God limits our suffering (1 Cor. 10:13)!