FINGER IN MOUTH

IF u remember ur childhood u may have gone through this very bad habit.......always keeping one or two fingers in mouth.....either cutting the nail or sucking.....and the saliva coming out.
Recently on X-mas day, we went to a friend....as usual they brought cake, sweets, chakli etc. ....while we were talking and taking small bites. ....the son of his tenent came and put his hand from mouth to the plate.....i scolded him, but in vain....he repeated 3-4 times....my friend also was silent because of relations or he did not want his mood off.......the boy was so obstinate that i felt bitter...but no use......this was his ADDICTION.......and on this addiction his mother or father also went rough but the boy was serious about his habit.......and he was beaten also but his adamancy astonished me.....WHY THEY DO NOT COME ROUND..... whose fault is this....naturally of parents...if they taught him in the beginning itself...he wud not have gone this much...disobeying others also. Lord forbid.