If you do not know what you are doing (. you used steroids with the most side effects, you abused the dosage, etc) then not only will you get bad side effects during the period of use, but you also will also get worst side effects after the use. Again, the degree of side effects is directly proportional to the dosage and type of the steroid and also dependent of the genetic propensity of the subject to get such side effects. Therefore, it would be impossible for me or anyone else to exactly predict what kind of side effects a user might encounter during a period of use. However, one thing is for certain. If you abused the drugs by using super high dosages and for very long periods of time, you may never be able to re-establish natural testosterone production, so you will then need to get with an endocrinologist and possibly stay on low dose testosterone therapy for life.
If taken properly with the appropriate doses, healthy eating and excersise then steroids are relatively harmless, no worse than smoking and drinking anyway. However steroids can be very dangerous when misused which is why I wouldn't advise anyone to take them without knowing all about the substance they intend to take, what dosages are correct and sticking to them, and just as importantly to know what aftercare is required after coming off the steroids. A good anti estrogen after a cycle is essential and sometimes required during the course of steroids themselves. Blood pressure should be monitored before and during use as a side effect which can happen is high blood pressure.
Unless someone has the correct knowledge, is prepared to take the precautions and knows the potential side effects and risks then there is no problem with them taking the drugs.
Unfortunately many take steroids not knowing what they are actually doing and encounter problems because of it.