Friendship is at the core of his latest production "My Friend Pinto", but acclaimed filmmaker Sanjay Leela Bhansali, who has had his share of differences with celebrities like Salman Khan and Farah Khan, says it is one of the most difficult relationships to sustain in the Hindi film industry.

"Friendship in Bollywood...it's difficult! Difficult because there is a lot of competition. People are very friendly, they are warm, they are nice...and there are a lot of people who are friends for long...but real friendship is tough here," Bhansali told in a candid chat.

The 48-year-old has reportedly gone through strained relationships with Ajay Devgn, Aditya Chopra, Rani Mukerji, Ranbir Kapoor and Sonam Kapoor, among others. With some, he had a war of words and with some, ego hassles.

Bhansali laments the conditional nature of friendships in tinsel town.

"Bollywood is a competitive place. But for me at least, if a friendship means that I have to work with the same actor and the same actress because that's what friendship is, then that is not friendship for me. That becomes a liability -- a liability that you are bound to a person," he said.

So what's an ideal friendship for the filmmaker?

"I feel a good friend in the industry is a person who says..'Ok, you've made a film with me, we had a great working relationship. Now if your other script demands another person, it doesn't mean you're taking anything away from me, or you are betraying me or backstabbing me.'

"I feel that is not friendship and if that is what friendship means, then I would rather stay away from that kind of friendship in the industry," he said adding that as a filmmaker, "I want the freedom and the liberty to say that my script is my god, and my screenplay is the most important - I have to be honest to it."

"But in Bollywood, if I have worked with a director, an actor, an actress and I do not repeat them, then there is no friendship. To put it simply...equations with people here change from film to film," he said.

A recluse, Bhansali, known for films like "Hum Dil De Chuke Sanam", "Devdas", "Black" and "Guzaarish", has few friends in the industry, but he isn't complaining.

"I, in particular, might not have had too many friends in the industry, but I do not have enemies either. A good, healthy relationship with colleagues is what this industry needs, and I have tried to find and keep healthy relationships," said the filmmaker, who feels he can always go back to people like Salman and Farah, despite their past differences.

Bhansali had a tiff with Farah over the clash between the release of his "Saawariya" and her "Om Shanti Om" in November 2007. Salman, who featured in the director's debut film "Khamoshi - The Musical", made nasty comments on the former's "Guzaarish". But they have let bygones be bygones.

"A friend will start off exactly where he left it and Farah Khan stands for what I am talking about. We had a problem...but I knew if I go to her with a film, she will start from where we left.

"There are good friends like that...Salman has been a very good friend over the years, and so have lots of others," said the National award-winner, who is producing "Shirin Farhad Ki Nikal Padi", which marks Farah's acting debut.

Bhansali also finds a true friend in former beauty queen Aishwarya Rai, with whom he worked in "Hum Dil De Chuke Sanam" and "Devdas".

"Aishwarya came to work with me on 'Guzaarish' after I did two films - 'Black' and 'Saawariya' without her. And I started off with her exactly from where I left it. She makes a good friend because at least I didn't have to give explanations of why I didn't cast her in 'Black', and in 'Saawariya'."