How tall are you? Do you see yourself as a big fella or medium/small etc? I have trained for three years and have made good gains, yet when looking at some lads who are juiced, you really do see the difference in simple mass, muscularity etc (unless they don't eat right and train like shit) and it makes you realise you have a long way to go even if comparing yourself to professionals or just the big lads down your own gym. I guess some people juice to get super huge over a certain period of time or maybe cause they're complete super hardgainers and don't seem to get anywhere or simply just impatient. Remember, if you have a hobby or sport you participate in, you always want to be good at, or one of the best, if not the best so to enjoy it more. Same if your a weight lifter/bodybuilder. You always want to be stronger, always want more chest mass, quad sweep and the alike etc.It's just general competitiveness and enjoyment. If your a professional bodybuilder, trainer, sports/athlete etc. then the reasons become obvious. I myself, would only juice to get bigger for personal satisfaction, to be big, strong, confident etc. would definately have a bash at competing too if I felt I was big enough.