Background. The spread of affective content on social media, as well as user grouping based on affect , has been a focus of scholarly attention for over a decade. But, despite this, we lack evidence on what roles various particular emotions play in the dynamics of discussions on social media. Emotional contagion theory (Hatfield et al. 2014) adapted for social media suggests that diffusion of emotions happens on individual level, via direct one-time contact with emotionalized content . Other theories, like theories of social influence or social learning , thought, suggest multiple, hierarchical, and/or topically-restricted contacts. The idea of affective agenda  implies that the dynamics of an emotional discussion needs to be assessed on the aggregate level. The question remains – what role the emotions taken on aggregate level play in the discussion dynamics, being either catalyzers or inhibitors of the discussions. One may suggest that emotions of different stance (positive/negative) may spur/slow down the discussions in various ways. Objectives. We analyze the spread of two polar emotions – anger and compassion – in three Twitter discussions on inter-ethnic conflicts, namely Ferguson protests (the USA, 2014), Charlie Hebdo massacre (France, 2015), and mass harassment in Cologne (Germany, 2015–2016). By analyzing the co-dynamics of the overall discussions and these two emotions we can conclude whether the pattern of the spread of emotions and its link with the discussion dynamics is the same in various language segments of Twitter. Data collection and methods. The data we use were collected by our patented Twitter crawler in the aftermath of the conflicts and include altogether over 2,5 M tweets. We used manual coding by native speakers and machine learning to detect the emotions; then, we visualized the dynamics of growth of the emotional content of the discussions and used Granger test to see whether anger or compassion gave a spur to the discussions. Results. We have received moderate results in terms of the dependence of the number of neutral users upon that of emotional users, but have spotted that the beginnings of the discussions, as well as the discussion outbursts, depend more on compassion, not on angry users, which needs more exploration. We have also shown that the hourly dynamics of emotions replicates that of the larger discussion, and the numbers of angry and compassionate users per hour highly correlate in all the cases.