Definetly not good for your liver. It actually increases your tollerance levels to the drug requiring more for the desired effect in the future. Its much like how drug addicts require more and more of their chosen drug to get a kick. If you have certain levels of paracetamol in your blood the whole time, the next time you get a headache (or whatever), you have to raise the level higher for the same effect. This is where the doseages can really knacker your liver.
Not trying to be too pesemistic, this is all a longterm process. See if you can get away with taking one paracetamol each time or just try doing without it. Its not essentially a drug for the mildest of symptoms and shouldnt be abused.
I definetly say that 2 a day is not a good habit.