As explained earlier today, today's Missouri caucuses were not necessarily binding when it came to delegates selecting a candidate. But people were passionate nonetheless, according to this AP report in USA Today:
"Contention and confusion marred various Republican caucuses in Missouri on Saturday, and one meeting was abruptly shut down, as impassioned supporters of Rick Santorum, Mitt Romney and Ron Paul battled for an edge in the state's complicated delegate selection process."
And the report also indicates the state may not be the boon it was to Santorum when he won the primary in February (a primary where no delegates were awarded):
"But Santorum didn't sweep the state, as he did in the February primary, for which none of the other candidates campaigned. Romney carried some township and county caucuses Saturday, and Paul also fared well in some places."
He did, however, win some delegates, as detailed earlier today. Again, unless the caucus voted to make their results binding for a candidate, there is no commitment to do so until the delegates chosen convene later in the year.
At this point, Santorum needs all the delegates he can get to keep pace with Mitt Romney; losing any caucus to him in Missouri makes it that much more difficult to catch up to Romney and keep momentum going in other contests that may not be as favorable to Santorum, such as the Illinois contest coming up.