Namaskar everyone, recently Tulsi Bahan from Italy wrote me an email. You might have often noticed it while watching bollywood movies or talking with native Hindi speakers. It is about addressing oneself by HUM instead of Main.
Here is the piece of email Tulsi sisters sent me :
From Famous Bollywood Song Hum Tum Ek Kamare Me Band Ho
Movie Name : Hum Aapke Hain Kaun ? ( Who am I of yours ?)
There are 100s of example in Bollywood where they use HAM हम over Main मैं.
3. You might have heard of sweet Hindi Lucknow, people they are very sweet & respectful Hindi/Urdu, similarly people in Jodhpur. They always use Plural form to address even to their servants.