Smiley/Sad Face

I find anything to do with Computers mind-numbing and really don't care how or why they work but years ago i sit in on a lecture by the British Psychological Society (BPS) about 'Psychology and the Virtual World' because i thought it sounded interesting. Turned out it wasn't because it was all about how websites can use Psychology to make themselves more appealing, something they called Cyberpsychology.  
This must have been mid 2010's i guess and looking at my notes it seems i either fell asleep or noticed something more interesting out of the window because they are very sparse but piecing together my scribblings i can see that Cyberpsychology is the scientific study of our psychological experiences with digital technologies and aspects of the internet.
Yep, a yawnfest indeed but according to them: 'It is important because in contemporary society, technology and the internet form such an important part of our everyday experiences. Technology is very much a part of how we socialise, how we entertain ourselves, how we work, and how we learn. Psychology is all about understanding human thought and behaviour, but critically we want to know how this works in 21st Century society. This is where cyberpsychology can give us a unique perspective about contemporary human behaviour.' Apparently.
I did have notes on emoji's and how we process them because they are a significant part of online communication and people’s expression of emotion.
According to whoever it was, we process them in the way we do with other emotional stimuli such as faces or emotion words. We can use methods from other areas of psychology such as cognitive psychology to test this experimentally. Generally, what we are finding is that on an unconscious level, we don’t seem to process emoji like other emotional stimuli. And that’s really interesting in itself'.
To them maybe, not so much to me because i drew a little smiley face which was more ACIIIIIIID from the 90s than the smiley emoji face they were thinking of but certain personality traits seem to be related to the type of emoji people use based on extraversion, agreeableness, conscientiousness, openness to experience, and neuroticism.
The most common used Emoji and Personality Clues to the people who use them are:

Happy/Smiling Faces (😊, 😄): Often linked to being agreeable, conscientious, and open; they add positive emotional tone, making communication clearer.
Heart Emojis (❤️, 🥰): Strong indicators of high agreeableness, showing warmth and affection.
Positive Emojis (🔥, 🎉): Indicate an energetic, enthusiastic, and hype personality, bringing energy to messages.
Negative Emojis (😠, 😥): Can correlate with higher neuroticism or mood instability, though they're also used to avoid awkwardness.
Thinking Face (🤔): May suggest deeper thought or intellectual curiosity, although not always linked to specific Big Five traits in studies.
Praying Hands/Monkey (🙏, 🙈): Can suggest a tactile nature.

I hardly ever use emojis which apparently shows 'discomfort with intimacy and distance themselves from emotional expression in digital messages', or i'd go with feel that there are no need for them if you write the email clearly in the first place.