Each one of us have certain peculiarities in our behaviour. As long as any habit of ours is not disruptive to self or others it does not call for any concern.
From what you report it seems that this act of tearing stickers is bit of a compulsive nature. Try and notice if not indulging in this act creates any anxiety in you. Notice if there are any other such habit patterns in you. Also to stop yourself from indulging in this, try to involve yourself in some other activity or put your mind into something else. Relaxation exercise would be of help. You could also consult a professional psychotherapist in your area in case you experience anxiety.