The free form nature of the input file is essential to the
spirit of TEX. As we type, we do not concern ourselves with linebreaks
and pagebreaks so much as the content of what we are typing. In fact,
we'll see that TEX will choose nice line breaks even for bizarre looking
input. This is just part of the concept of only having to describe the
logical structure of the document to LATEX, and not worry
about nuisance-value formatting details. We inform LATEX of the logical structure of our document by telling it when to begin
a new paragraph, subsection, section, chapter, theorem, definition,
remark, poem, list etc. When typing a particular element of the logical
structure, we need pay little attention to how we lay our source file out.
A consequence of this is that we have to go to a bit of effort to mess things
up. Starting a new line, for instance, entails more than just pressing
Return because LATEX will just regard the next word you type
as exactly that—the next word in the paragraph. You have to specifically
ask for a line to be terminated. Things like this may seem to be a bit of a
nuisance, but it is a small price to pay for the automatic formatting that
necessitated it. Further, such small inconveniences have been localised
to rare events. I have, for instance, not once forced a new line up until
this point in the present document.