Unfortunately, as an English teacher I have come to realise that sometimes you have to accept the answer:
just because it is
This fits particularly well with this question, where the answer really does appear to be
because it sounds right.
As a few have mentioned, existing collocations will already have their precedent, so "chips and fish" or "dogs and cats" would simply sound wrong to many because of their well established forms.
In the case of listing items, I would say that every case is different. Depending on the contexts of your lists, you may have differing priorities. Sometimes 'order of importance' is relevant while others 'alphabetical order' may seem appropriate.
When nothing like this is involved, however, we most often revert back to "because it sounds right".
Exactly why it sounds right can again be different in each case.
Just to mention one, the ease/difficulty of producing a sound often plays a large part. For example, two vowel sounds meeting is abnormal in English and so when we have an instance of it, we tend to avoid it:
(I'll use people's names as the example because, as I said above, other objects tend to have a context that dictates priority.)
Mike and Eva (not 'Eva and Mike' because of the uncomfortable stop between the two 'a' sounds)
and for the cynics that believe we always put men first:
Janine and Dara (not 'Dara and Janine', for the same reason).
and for those who insist on something other than people's names, consider:
'a banana and an apple' -or- 'an apple and a banana'
Indeed, it is for the same reason that we have two indefinite articles, 'an' and 'a'.
There are languages where double vowel sounds are quite normal and this explanation would not apply. However, for English speakers learning these languages, the unfamiliar sounds are the hardest to acquire, naturally. (In Indonesian, sorry is 'maaf', pronounced 'ma-af', which just feel uncomfortable.)
There would be many other reasons to mention, but I hope this shows how there is slightly more to it than the sometimes apparent randomness.