I think it's very tiring but here in the US, the major grocery store chains have really good pay and benefits.

Did you search for the grocery store here on the internet to see if they have a page about them/working for them? Having a clue who the owner/officers are and where they're located, etc. might give you some idea of something to say during the interview so it looks like you care :-) See if you can think of a question or two to ask or a way you think you'd be an asset to their store(s), etc.