The power of the subconscious mind

YF was telling me about his hostel life during his uni days. He shared a room with this very studious and pious guy. That guy used to study in the wee hours of the morning while listening to Christian songs. Y was oblivious to that and just went to bed every night till he realised that he was singing those songs while bathing one morning. He immediately told his room mate about it and his room mate promptly bought a pair of headphones.