fortunately most people already know I'm a big jerk, so no. I am able to use the same broken grammar and unprofessional nature both in work and personal emails.
I'm probably the biggest abuser of smilies there ever was. It's rare that I send an email or forum post without adding one or two in for good measure. Mostly because I tend to joke a lot and want to make sure what I said is construed as a joke.
Edit:
^I had to add them in on a post that says I always use smilies I don't use any go figure!