I was buying some carry out and I asked for a nylon bag. The cashier, who is not a native speaker, gave me a look and offered a 'plastic bag', which is what I wanted to begin with.
I don't know why I used "nylon" instead of "plastic"; I'm not a native speaker but I'm fluent in English and that got me thinking:
Is there any difference between "nylon bag" and "plastic bag"? Can they be used interchangeably?