There are many dangers you face when taking steroids for muscle enhancement.  Not only are you facing the moral degrevation of cheating, but you are also harming your body.  See the following picture for reference on the side effects of steroids.

     As can be seen, the effects of steroids on the body are both physical and mental. Naturally, the body produces a vast plethora of hormones through the endocrine system which regulate and control the various processes of life. By using steroids, one sets this carefully regulated balance into chaos. This imbalance causes the various effects shown above. Likewise, many of the effects of steroids are irreversable. For example, with the use of steroids, the body's natural production of hormones becomes weakened. Once the usage has stopped, the body is unable to completly revert to it's former homeostasis (the body's state of balance at which it functions most effectively).

     For individuals who inject steroids into their muscles, and who share needles to do so, the possibility of contracting HIV or AIDS is increased.  In addition, a person can also develop "roid rage," which is sudden, uncontrollable, and violent behavior brought upon by the usage of anabolic steroids.  This sudden rage can be harmful to the person themselves or people around them.  A pro-wrestler, Chris Benoit's roid-rage resulted in him brutally murdering his wife and son, and then hanging himself.  Thus, as you can see, Death is also a risk.  

     All in vain? The answer is yes. A large amount of the muscle mass gained from the use of steroids is often lost after the usage ends. The long term benefits of steroids are therefore diminished; and this becomes only a negative, life damaging habit.

     While comical, this picture accuratly displays some of the notorious effects of steriod use. The hormones of the body hold much control over the mood and disposition of an individual. Interrupting this natural hormonal cycle can cause havoc in a person's general attitude, thus causing major complications to their relationships and everyday life, which is evident in the facts related in the following links as well.

http://www.lycos.com/info/steroids--people.html

http://kidshealth.org/teen/drug_alcohol/drugs/steroids.html