Principles of freedom
One of our guru's was once asked - "what do you have to give up to become a monk?". He immediately replied "just give up suffering!" It really was spot on. The monastic life is a simple, sublime and happy life, free of worry and anxiety.
That’s not to say, however, that there is no strictness. As monks we refrain from intoxication, meat eating, gambling, and maintain vows of celibacy. These principles liberate one from the dictates of the mind and senses, and allow one to function on the level of spiritual inspiration. Far from limiting the person, such principles help the person to develop a higher consciousness and awareness, enabling them to really exercise free will in the consumerist world we live in.
If a man was jumping off a cliff and a friend demanded "DON'T jump!" - that friendly advice (restrictive as it may sound) would significantly affect the man’s ability to exercise free will in the future. Restriction is not opposed to a freedom. Accepting vows of restraint do not obliterate one’s opportunities for happiness, but instead open up a whole new realm to discover.