## 1 Introduction
### Goals and Contributions  
As a result, the objective of this systematic literature review (hereinafter SLR) was to identify and gather primary studies through a basic search string focused on the happiness and unhappiness of agile software development communities. Furthermore, it establishes the geographic distribution of the primary studies, examines the main scientific initiatives on SD in agile software development communities, which have been found and categorized using the classification scheme proposed by [PERSON] et al. [19], and collects relevant information such as definitions, concepts, the quality of the primary studies, citation counts, causes, consequences, challenges, future work, and existing contributions. The defined basic search string was adapted and applied over an 11-year period, from 2013 to 2024, and was used in six search engines: IEEExplore, SpringerLink, Scopus, Google Scholar, Science Direct, and Web of Science. After analyzing the information gathered from the selected primary studies, it became evident that, although there is a limited number of studies related to happiness and unhappiness in agile work communities, interest in this topic has grown significantly in recent years due to its influence on critical aspects related to the quality of life (physical, mental, and spiritual health) of professionals within software development communities, and how these aspects positively or negatively impact the value of the deliverables and project costs [8; 10; 17; 18; 19; 20].  
Additionally, the SLR revealed that there are causes and consequences related to happiness and unhappiness in development communities. However, most identified causes and consequences in the literature are ambiguous or lack a formal definition. This means that the community's perception can be subject to different interpretations, be uncertain, and even generate confusion. For example, two or more causes (or consequences) may have similar names but refer to entirely different aspects, or they may refer to similar elements but have different names. Moreover, it is important to mention that a large portion of the identified literature focuses on the negative impact of poor or nonexistent management of SD or certain social, psychological, and emotional aspects of software communities. For example, the focus of the identified studies is primarily on unhappiness, which reveals that the literature has identified issues related to SD in software development communities that were not previously considered. This provides a different perspective, where individuals are not only viewed as tools with technical knowledge and skills capable of achieving organizational objectives through high-quality standards and continuous value delivery in the products developed, but also as individuals with emotions and feelings who are affected by their environment, interpersonal relationships, mental health, and the work they perform. On the other hand, it is also important to highlight that no studies were found that present concrete results regarding the percentage of happiness achieved in companies that use complex organizational structures, such as remote work and/or global software development, where physical contact and personal interactions are practically nonexistent [11; 21]. Similarly, the studies identified in the literature tend to approach happiness as a means for development communities to be more productive. Still, they do not delve into the mechanisms, strategies, or elements necessary to achieve or manage it.  
This SLR is structured as follows: Section 2 presents the research protocol used for the SLR and the execution of the information search. Section 3 presents the results obtained by answering the research questions. Section 4 discusses the results, the main observations, the limitations of the review, and the significance of this research. Finally, Section 5 presents the conclusions and future work.