SpamAssasin sometimes gives a very high score for "shouting". The message it gives is:
BODY: HTML has very strong "shouting" markup
This can appear when there a lot of <b><string><i><H?> tags. or even if you have only a few of these tags and the tags are not properly closed.
<i>click here. Followed by some other text. original i is not closed and we now have another <i>italic