stubbornness

Why is one's habit or likes so hard to get over? I have all the while since young been in the know that I am kind of lactose intolerant and that drinking milk or any of the likes like coconut milk will get me running to the toilet for at least 3 or 4 times shortly after I consume the milk. With this in mind, some people would have stayed off milk for like their entire life, but well thats just not the case for me. I've always had this thing for milk and milk related stuffs and I just cannot stay away from it. So well I just always repeat the routine of being in pain and running away to the toilet after drinking but yet I never learnt my lesson. Sigh, I guess I can never get over this like so well for now I'll just make sure before I drink milk, I shall make sure there a clean toilet in the near proximity available for use. Tsk, my ramdom rantings are starting again =)