Never believe anything blindly
The influence of Sree Ramakrishna Paramahansa in moulding and guiding the character of Swami Vivekananda, is well known. Though Vivekananda, revered Ramakrishna, he never accepted his teachings at face value, he always questioned him, debated with him, and it was for this reason that he was the latter's favorite disciple. Once Ramakrishna claimed that he was so allergic to money, he could never really bear even it's touch. In order to test him, Swami Vivekananda placed a coin under his mattress. When Ramakrishna sat on it, he began to experience a stinging pain, grew restless and started to cry out. He raised the mattress and saw the coin, demanded to know who put it there. Vivekanands claimed he did it just to test Ramakrishna's claim, the latter was pleased "You are right Naren, never believe anything blindly, test it".