We have introduced an author sentiment benchmark of emoji and we have compared it with a writer sentiment benchmark. We found that readers and writers seem to broadly agree on sentiment of emoji (84%) even though the reader's source of comments were tweets and the writer's source of comments was an anonymous work-happiness monitoring app where comments refer to work suggestions. The largest disagreement between readers and writers occurs for negative emoji (sad face, pouting face, etc...). For this group of emoji, the authors report to feel 26% worse than what readers perceive in terms of standard deviation. Emoji use was not found to be correlated with author moodiness. Emoji use was found to be correlated with more happiness within users and between users. We hope this results will improve the accuracy of sentiment estimation of authors and writers of when emoji are used