You are easily shrugged off as unimpressive. Your verbal jabs and body language don't communicate that you mean business. Maybe you're quirky, feeble, deeply strange, or slow on the uptake. Whatever the cause, it is so apparent that people have a hard time taking you seriously. You take a −2 penalty on Intimidate and Taunt checks.
Everyone except the Cowardly or other Laughables will repeatedly brush you off. However, just because you don't seem particularly dangerous doesn't mean you aren't, in some fashion.