now my problem is, that if i am right that it is like a diet, than in a diet we know, that you can cheat here and there.... So why is it so important never ever to masturbate or watch porn?
Because food is necessary and good for you.
Extending your
mashal, could you say the same thing for
treif and
kosher? That you can just have a little
treif and it's OK? After all, we know it won't kill you. How about
Cholov stam and
non-glatt? Is it different for different people?
Flogging the metaphor to death, one could argue that movies are like
Cholov stam - they'll do no perceptible damage to some people, but lots to another. When I see a
Chossid in full-uniform chomping away at a Hershey's bar where he thinks nobody "important" will see him, I know he's probably falling in other areas. When I see the Mod-Ox kid doing the same thing, I think nothing of it.
If you think it's wrong -
it probably is. The two hard parts to this are (a) being honest with yourself, and (b) acting on it. Hiding something is a very good way to determine if you consider it wrong... As we discussed at some length via PM.