Alonso's decision to leave F1 at the end of the 2018 season was motivated by a number of factors. Firstly, the Spaniard had become increasingly disillusioned with the sport's political landscape and the direction it was heading in. Secondly, he had become frustrated with the performance of his McLaren team and felt that he was no longer capable of fighting for race wins and championships. Finally, Alonso also had one eye on his legacy and didn't want to be remembered as a driver who spent the final years of his career struggling at the back of the grid. All of these factors came to a head at the end of the 2018 season, and Alonso decided to call time on his F1 career.