Question

why did patol babu doubt that the film unit people were able To appreciate his work?

Answer 1

because there were a whole lot of people working in the film. Patol Babu saw that  no one there had enough time to appreciate someone's work. Also, his role was a small one and did not carry that much imp. Moreover, it was only him who knew that how much hardwork and dedication he had put in in that short role of his.
Hope this helps. Thanks