As an extension of traditional trope of shoulder angel and devil traditionally depicting people's good and evil side, several EGS characters have some anthropomorphic personification of different sides of their personality. Several others at least have internal discussion visualized in similar way: sometimes it's hard to say which is which due to only seeing it once.
Susan was first whose internal conflict was depicted that way, when she was thinking if she will go to Grace's Birthday Party:  The sides depicted were curiosity and logic. Interestingly, Susan was acknowledging them and arguing with them.
When Catalina tackle-glomped Elliot, we saw visual representation of his mind with multiple sides, some showing transformations he have. Included was the hero side, shy side, logical side and libido side, along with two harder to identify ones.
Sarah's sides were extremely situational: when she got O.P. Aludrakrala card in Magickal Gatherings tournament, one side of her personality appeared as vampire and tried to convince her to play vampires to win, while another appeared as werewolf and argued for using creativity and making themed deck. After presenting their arguments, Sarah got another idea - to combine vampires and werewolves with narrative of werewolves trying to reform the vampires ... meanwhile, her vampire and werewolf sides fought in background.
After Larry learned that Sarah would go on a date with Sam he had an internal argument on whether Sarah was a hypocrite since she chastised him for hitting on her. The sides weren't the traditional angel and devil even though one side can be seen as representing the pick-up artist ideology.
Diane's sides were traditional angel and devil, although the devil is more of a jerk than really evil. Also, both are dressed like cheerleaders. They appeared to comment about Diane "guessing" that Charlotte never was on date.
Pandora had several long talks with other aspects of herself.They were shown as separate entities when she was deciding if she wants to reset, although in her case we can't rule out they were physically present (or, well, present on spiritual plane or whatever).
Grace had an internal debate on whether to give Sam access to Tedd's magic. The sides were her logical side represented as businesswoman and emotional side represented as a hippie (both, however, part-squirrel).
Nanase's angel and devil appeared to decide if she should trash-talk Diane to Susan. They appear considerably more distinctive than Diane's. Interestingly, Nanase's angel side is completely different from her Guardian form. This is the first exception to the tendency that the main characters don't have evil sides in their internal debates (except Diane, who used to be a jerk).
Tedd's first shown internal debate is even further away from good versus evil than Sarah's: seems his conflict is between his "pervert" side and/or libido represented by hot woman, who sees transformed Elliot as hot, and some ever harder to specify side, which is overwhelmed by how casually and confidently Elliot turns into hot woman in semi-public content, represented by ... ok, apparently also female, but usual androgynous one.
- ↑ egscomics tumblr post ID 190039889603 ("while-weve-seen-representations-of-various")
- ↑ EGS Main Story Comic for 2005-01-14 ("Yay! I've Been Looking Forward To This Bizarre Sequence For Months!")
- ↑ EGS Main Story Comic for 2008-06-16 ("Susan's Nature VS Nurture")
- ↑ EGS Main Story Comic for 2012-03-15
- ↑ EGS Main Story Comic for 2013-11-05
- ↑ EGS Main Story Comic for 2014-05-19
- ↑ EGS Main Story Comic for 2014-05-22
- ↑ EGS Main Story Comic for 2014-05-26
- ↑ EGS Main Story Comic for 2014-12-10
- ↑ EGS Main Story Comic for 2015-01-11
- ↑ EGS Main Story Comic for 2017-01-02
- ↑ EGS Main Story Comic for 2017-08-14
- ↑ EGS Main Story Comic for 2018-12-07
- ↑ EGS Main Story Comic for 2020-01-03
- ↑ EGS Main Story Comic for 2020-01-15