Why did i say 'Sai baba' when i saw Lord Shiva, though my favourite GOD is Srio Rama?

Jai! What a blessing, that you were visited by God in your dream! The Supreme Personality of Godhead is one. Therefore, His names, fame, qualities, and forms are one. Sri Rama is our maintainer, and Sri Shiva is our destroyer. You committed some slight offense (wearing your slippers), so Lord Shiva wants you should offer Him sacrifice, which is why you saw lingam. Offer your obeisances to Lord Shiva, so that your son's health will be returned.