It is interesting though. Looking back at chat history. If I am not writing multiple sentences, and even sometimes when I am, I tend to leave off the last period.
I think emoji reactions to messages, especially in off topic channels, are totally reasonable. And certain ones (+1, -1, 100, etc.) are OK for technical discussions. But don't feel people should be adding faces into the actual content of on topic work messages. But, the actual context in those conversations should be clear, and make them unnecessary.
One thing that actually drives me nuts is when people will keep their messages short. Write 5-10 words of a thought out, hit enter, and keep on going. You end up getting 7 notifications in quick succession, and none of it is complete. Please, just write out your entire though out as one singular cohesive message.