#3 Cristiano Ronaldo has not won the FIFA World Cup with Portugal
Just like Cristiano Ronaldo, winning the FIFA World Cup is any footballer's dream. But football is a team sport and even if a side has the best player in the world in their lineup, all the individuals have to come together and go over the line together. Suffice to say, there are a lot of variables when it comes to winning a tournament.
The farthest that Portugal have gone in a World Cup since Cristiano Ronaldo broke into the international side is the semi-final in the 2006 edition. They crashed out in the group stage in 2014 and only made it until Round of 16 in the 2010 and 2018 editions.
By the time the 2022 World Cup arrives, Ronaldo will be 38 and his powers will have waned. But Portugal do have a raft of sensational players and so it wouldn't be wise to assume that they won't be able to win the World Cup in 2022. As such, this is something Ronaldo could yet chalk off from his list of regrets.
#2 Failing to inspire Juventus to the Champions League title
Juventus were absolutely unstoppable domestically when they decided to sign Cristiano Ronaldo. They were willing to shell out in excess of €100 million to sign him from Real Madrid to boost their chances of winning the UEFA Champions League.
The Bianconeri had come close twice in recent years. They were beaten by Barcelona in the final of the UEFA Champions League in the 2014-15 season and by Cristiano Ronaldo's Real Madrid in the 2016-17 edition.
However, since Cristiano Ronaldo joined in the summer of 2018, Juventus have crashed out in the Round of 16 twice and reached the quarter finals once. The Portuguese has not been able to inspire Juventus to a Champions League title.
The timing has not been perfect either. Juventus are a team that has been searching for a new identity and have changed managers twice since Ronaldo joined.
#1 Not winning as many Ballon d'Ors as Lionel Messi
Cristiano Ronaldo's and Lionel Messi's rivalry is one for the ages. We're blessed to have witnessed two of the best footballers to have ever played the sport battling for supremacy against each other at the peak of their powers.
Cristiano Ronaldo and Lionel Messi have enjoyed a duopoly of sorts over the Ballon d'Or for a decade. Ronaldo has five Ballon d'Ors to his name. However, Messi has six and given Ronaldo's competitive nature, he won't be satisfied until he can match the Argentine's haul or top it.
But Ronaldo is 36 now and with other players now making a strong claim for football's biggest individual prize, it might be really tough for him to catch up with Messi. If that's the case then it will be something that will stay in the back of Cristiano Ronaldo's mind.