It has been a good journey whenever I took an Indigo flight. I haven't had any dispute with any of the staffs and they are polite while communicating, sometimes too polite!
The most memorable one being with the ground staffs of Rajiv Gandhi Intnl Airport, Hyderabad. Me and six of my friends had booked online tickets from Hyderabad to Bagdogra via Bangalore through a connecting flight. When we reached at the airport, one of the ground staff told us that our flight has been cancelled. On hearing that we panicked but he convinced us that he will manage to board us in another flight. He contacted with his senior and his senior did his best to help us. I forgot his name now but I have given a positive review for him in their website as well.
A little disheartening incident was on my flight from Lucknow to Kolkata. I had asked a cabin crew for water in a polite manner but I still don't know if she didn't hear me or she ignored me. That was a bit rude of her.