This study aims to: (1) identify the main contributors to happiness and passion of non-professional UE athletes; and (2) explore the possible relationships between types of sport passion, motivation, and athletic identity. During data collection, 116 non-professional UE athletes (mean age 43.66 years, SD = 8.97, 16.4% female) responded to an online questionnaire. Statistical analyses revealed that obsessive UE passion (p < 0.05) and amotivation (p < 0.05) predicted lower levels of happiness. A higher level of obsessive passion was predicted by extrinsic motivation (p < 0.005), amotivation (p < 0.05), and exclusivity identity (p < 0.001); a lower level was predicted by social identity (p < 0.05) and years in sports (p < 0.05). Weekly training hours and age correlated positively with passion strength, while amotivation was strongly negatively related to training volume. These results indicate that happiness of UE
athletes depends on the type of sport passion formed and the quality of the underlying motivation: obsessive passion and amotivation seem to be the main enemies of happiness for UE athletes. This novel finding connecting passion, happiness, and motivation contributes to both a better understanding of the psychology of UE athletes and has practical implications for UE athletes, coaches, athletes’ social circles, and sport psychologists. Due to known maladaptive outcomes of obsessive passion, including its negative impact on overall well-being, health, and now also on happiness, its formation in UE athletes needs to be observed and prevented. While the study shows predictors of obsessive passion and high vs. low obsessive passion, future research should investigate how harmonious passion impacts athletes’ happiness, motivation, and identity. Likewise, research among the UE entourage would help to better understand the social impact of UE as a serious hobby and the formation of UE lifestyles. We also suggest our Temporal Framework for Progressive UE Engagement and Passion, which was further developed based on the results of this study, to be used and validated by sport psychologists.