Answer: Satan loves to see us suffer, so he delights in tempting us to disobey God and sin. God as our Creator is looking for our obedience while Satan as the destroyer is giving us every opportunity to ignore God and His way of life.
In the book of Job we find a man who feared God. Job was blameless, upright and turned away from evil yet God allowed Satan to test his faith, yet there was a lesson that Job needed to learn. Satan complained to God that He was putting protection around Job which allowed him to prosper both spiritually and physically.
Job 1:10-12 (ESV), "Have you not put a hedge around him and his house and all that he has, on every side? You have blessed the work of his hands, and his possessions have increased in the land. But stretch out your hand and touch all that he has, and he will curse you to your face." And the LORD said to Satan, "Behold, all that he has is in your hand. Only against him do not stretch out your hand." So Satan went out from the presence of the LORD."
Satan was allowed to afflict Job and destroy all that he had up to the point of great suffering. In this case, Satan was the instigator and the agent, but God allowed it to serve the great purpose of showing that we can prevail not by our own righteousness, but through humility and faith in the Eternal (Job 42:5-7).
One of Job's friends said truthfully Job 5:6-7 (ESV), "For affliction does not come from the dust, nor does trouble sprout from the ground, but man is born to trouble as the sparks fly upward."
Trials and difficulties can be expected and sometimes it is Satan and his demons that cause the suffering. The bible indicates that it is part of the process as we look forward to a new life in the Kingdom of God. Acts 14:22 (KJV), "Confirming the souls of the disciples, and exhorting them to continue in the faith, and that we must through much tribulation enter into the kingdom of God."
Whether this tribulation is self inflicted though our own bad choice or if God allows Satan to take us down a notch we can rejoice in knowing that it is for our ultimate benefit. The bible calls Satan "the destroyer." He is the thief that wants to steal kill and destroy our lives and cause us to suffer. God has a much different plan for us as we look forward to abundant eternal life His Kingdom
John 10:10 (ESV), "The thief comes only to steal and kill and destroy. I came that they may have life and have it abundantly."