The Friends List Adder:

Can be either a blessing or a curse, simply by multiboxing you get a large amount of people keeping you on their friends list. While this can be good that people always ask you to join their instance groups, most of the time they fill the other slots with a horrible tank or healer, or have four dps in one group. And when you're busy, you get constant tells "Do you want to hit up XX instance?" Since there are so many of them, it's nearly impossible to remember who actually knows how to play and who is just a multiboxing-fascinated although unskilled player (I've had a few just watch me, sitting there and only marginally helping out the 5 man group)

The Neutral Town Camper:

Opposite faction only. When they see a multiboxer, they call in their entire guild and kill you in a neutral town such that it's impossible to even hand in a quest, spamming "XX claps for you, clearly unimpressed" emotes. They may pay hundreds, if not thousands of gold in total repair bills from dying to neutral guards, but they have satisfaction! Surely killing a no-life basement dwelling multiboxer makes them experienced socialites.

The Watcher:

Follows you around, but from a distance. Can be from either faction. Always stays on mount or in stealth. Never says anything but just watches you for a very very long time as you quest, do dailies, etc.

The Foreigner:

Believe it or not, I've had tons of people try to talk to me in Chinese. Some of them actually seem legitimate though... When I first started my team in valley of trials a level 1 female orc warrior kept speaking to me in Chinese and it was obvious she was trying to find out how it was being done! (I have basic knowledge in Mandarin)

The Pauser:

When riding past you doing city errands, stops, turns towards you for a second, scratches their head and runs away.

The Multiple Emoter:

Feels that they have to repeat an emote targeted at each character, because "Greeting everyone with a hearty hello" is not nearly as good as 3 separate emotes.