Gym is newest religion. The activity and prospects are far too commonplace, and now contemporary society, at least for men, requires that one must participate in the trend. The notions that follow the gym are often grounded in narcissism and the will to achieve some level of sexual appeal.
Look to anyone spreading the gospel of the gym. Two points are most commonly proposed.
1) Discipline, masculinity, self control, blatant fucking narcissism. These are attempts to please the intrinsic human need for social dominance.
2) sexual appeal: People who go the gym do it for sexual appeal, even when otherwise stated.
When you realize these things, you notice that these are all attempts to satiate preliminary drives that ultimately arrive at the same point of conclusion.