We don't know where to start this. Actually, we do - this man needs to turn his t-shirt around, messages should always be on the front! Other than that, the only thing we can assume is that something very specific has happened, his friend is upset with him, and he thinks the only appropriate way to apologize is to walk around school wearing a t-shirt which offers a full apology.
After seeing this, we have questions which will never be answered. Does anyone really get that upset about being called a duck? Does calling someone 'little friend' convey the right sort of tone for an apology? Why did he think his friend was a duck in the first place? We love how he thinks he was just 'hasty' in his assessment, rather than completely wrong! Ever looked at someone you know and thought they were a duck for a split second? No, us neither.