Thousands of users post on Reddit every day, but a fifth of all posts are removed. How do users react to these removals? We conducted a survey of 907 Reddit users, asking them to reflect on their post removal a few hours after it happened. Examining the qualitative and quantitative responses from this survey, we present users' perceptions of the platform's moderation processes. We find that although roughly a fifth (18%) of the participants accepted that their post removal was appropriate, a majority of the participants did not --- over a third (37%) of the participants did not understand why their post was removed, and further, 29% of the participants expressed some level of frustration about the removal. We focus on factors that shape users' attitudes aboutfairness in moderation andposting again in the community. Our results indicate that users who read community guidelines or receive explanations for removal are more likely to perceive the removal as fair and post again in the future. We discuss implications for moderation practices and policies. Our findings suggest that the extra effort required to establish community guidelines and educate users with helpful feedback is worthwhile, leading to better user attitudes about fairness and propensity to post again.