I would also like to thank the support and cooperative work of my lab mates Réka Kassai and Ádám Koncz who contributed in some of the projects with their ideas, co-writing, and experience. Also, I would like to express my gratitude for my colleagues from ELTE Anna Veres-Székely and Zsofia Logemann, who helped in some of the projects. Many thanks for the psychology, educational science students who participated in the doctoral projects during the data collection, and the mindfulness intervention.Lastly, I couldn't express more my respect and gratitude towards my family, who supported me in my studies and motivated me along the rocky road. Many thanks to my mother Margit Váradi and my father László Vekety, who raised me as an always courious and motivated child to learn for a life-long. Many thanks to my former teachers for not loosing this motivation but even making it stronger. I am grateful for my grandparents, Margit Földi, György Váradi, and László Vekety, that they always believed in the great power of education and encouraged me to learn. I would also like to express my gratitude for my friends and my partner Barnabás Tarkovács, without their permanent social support and caring I couldn't make it. Last but not least, I would like to pat my own shoulders for being persistent in doing all the tremendous work related to the PhD, and still keeping my enthusiasm and optimism. I am very proud for all of this.