Random exclamation points inserted into emails

I use PHP mail() to send out emails quite often. I recently found out that if you create your email as one long string without line breaks, you'll get random exclamation points in your emails. I was recently pointed towards RFC 2822 section 2.1.1 for the solution. It appears that no line can be longer than 998 characters without a line break.

How do you fix this? (1) The first way is to base-64 encode the data (best solution for plain text emails to retain long lines). Check out this blog for some info on that. (2) The other, much easier way, is to simply insert line breaks in your email (best solution for HTML emails where long lines are not needed). Add a "\r\n" to the end of each line in your email to make sure you never go over 998 characters.