The great food debate

Does the type of food we feed our dogs really make much difference to their behaviour?

Should we feed wet or dry? Top of the price range or a more sensible price?

Someone told me, "If the dog likes what goes in and you like what comes out - that's fine!"
As I have a somewhat "excitable" 15-month-old Golden Retriever - I wondered if you could give me some advice as I don't want to swap and change his food for nothing?

Thank you,

Wendy, by email