Dear Mister Busdriver,
Hereby my friends and I would like to apologize about yesterday night.
Being dressed up ourselves made us assume everybody around us was dressed up as well.
Honestly, we couldn't help the fact that we had never seen you before, so that we didn't know your hair looks like Elvis everyday. We just thought we did a pretty good job recognizing the personality you wanted to be for Halloween.
We are sincerely sorry if our remark about your Halloween hair-cut influenced your mood in any way. Actually we thought you did a really good job.
Thank you for your time,