Some suggested interpretations of this message include:
“You may have already suspected that I was an asshole, but I have left you some documentation just in case.”
“I’m incredibly angry and not entirely sure who to blame so I lash out at everyone around me.”
“I’m mad about having to pay to keep the country running, and I’ve decided the most effective way to make my displeasure with this governmental policy known to the people responsible is to take it out my impotent rage on waitresses.”
This is a direct pickup from Boing Boing
When Bitter Republicans Tip (or more precisely, when they don’t)