There has recently come my way a question from a Protestant (who is, I gather, a professor) asking whether one "must" cross oneself, kiss the icons, and make a reverence at certain moments in our temples and homes.  
     The question clearly presupposes a legalist view of the questioner or of us.  While Orthodoxy has its canon law and certain requirements for certain privileges, the Orthodox world view (notably its view of the Fall and of Salvation) is not based on legalisms . . . such as the juridical teaching that the Trinity insisted on satisfying justice before He would deign to forgive our sins--and that Jesus was punished for our sins on the Cross--and much in like vein.
    The Orthodox look at the actions mentioned at the beginning of this page as ways of manifesting love in traditionally approved (and evidently satisfying) ways.  Since we adore the Cross and love what our Savior did on the Cross, we cross ourselves both out of love and to remind us of what Jesus did.  Since we love Jesus, His Mother, and the other Saints and revere the holy miracles or other events portrayed in icons, we show our love and reverence by kissing them.   
    One could expatiate at length.  But these examples show how radically different and how far apart the thought world of the "Western" questioner and the thought world of the Eastern Orthodox are.  We kneel or prostrate ourselves on days when this is permitted because someone (or public opinion) forces us to.  Indeed, one sees this person making a prostration now, another doing it at some other time, and practically everyone who able to do so doing it togther at a few other few times.  Each person does it as one is moved to do it by love and reverence.  We don't think twice when someone does or does not perform this act of humility and adoration.  When we beg the forgiveness of others on Forgiveness Lordsday just before the Great Fast begins, we kiss one another and (in some traditions) prostrate ourselves before each of them--not because we have to but, if we are sincere--because we think that the triple kiss and the act of humility respectively express our love for them and express how humiliating we consider our offences to have been.  If we do any of this for the mere show of it or out of obedience, the acts have no worth; indeed, kneeling out of routine would hardly have much value, and kneeling just to impress others would be hypocritical.