20 Reasons Why You Don't Like Certain People

Texts with a period at the end are perceived as insincere and/or angry.

Scientists from the State University of New York at Binghamton with Celia Klin as the supervisor held an experiment with 126 students. They had to read dialogues that consisted of only 2 lines: the first one was a question and the second consisted of different variations of answers such as “yes,” “yeah,” “sure,” and so on. The most important thing was whether or not there was a period at the end of the answer. After this, the participants had to evaluate the answer in terms of how true it seemed to them. And surprisingly, in most cases, the answers without the periods were evaluated as being more sincere than those with a period.