Well, you are taking a risk. People don't say they have adverse effects for no reason. Doing it once probably just isn't enough to notice them, people who do steroids typically do them on a regular basis in conjunction with exercise as far as I'm aware. I wouldn't recommend it personally, it's entirely possible to build muscle without steroids. Steroids will speed up the process and also increase your maximum potential while you're on them, but for a price. If you're not already a body builder then the increased maximum potential is redundant.
Steroid use can lead to psychological effects including: >Extreme paranoia/jealousy>Extreme irritability/aggression >Delusions>Impaired judgement >Mania
I'm not telling you how to live your life, I mean hell I do crack cocaine every now and then. You should know what you're getting into though. I wouldn't touch the stuff, personally. If you go natural then you'll only have positive physical and psychological effects. Seems more werth imo, even if it is a bit slower.