[Osiris]

I agree. I'm unclear how it decides what posts get shown and what is hidden in the "Load more comments" tag. I've even found responses to questions within those "load more comments" section, which I find odd. They are also completely out of chronological order.

[defrost]

If you open a submissions comments you'll see in the top left corner under the submission text and the empty "your comment" box a little drop down that says "sort by" ...

The default sort order is either best or top scoring which will rank comment order by vote score, I generally sort by "old" (oldest first; chronological order.

If you have an account you can alter your default sort preference.