There's no denying the fact that The Undertaker has had one of the greatest WWE careers in the history of the company, something which many young Superstars can only dream of achieving. Being with WWE for nearly 30 years, and having entertained millions of his fans all over the world, The Undertaker should be very proud looking back at his career.On the final chapter of WWE Network Special "Undertaker: The Last Ride", the Phenom seemingly announced his retirement from WWE, stating that at this point in his life, he doesn't have any desire to get back in the ring. Ever since the announcement, the wrestling world has been buzzing with fans, colleagues, and everyone in between thanking The Undertaker for everything that he has given to this industry.If you ask The Undertaker he probably would not choose to change much about his legendary run. After all, what more can a man want? But turns out, there are certain moments, segments, and matches in his WWE career, that The Undertaker is not so proud of. He would certainly like to go to back and fix a few moments from his WWE past.With that, let's take a look at the five biggest regrets of The Undertaker's WWE career. Be sure to comment down and let me know your most and least favorite moment of the Phenom's career.Honorable Mention: The "train wreck" match against Goldberg at WWE Super ShowDown 2019.#5 The Undertaker getting Sara's name tattoed on his neckReminder: The Undertaker used to have his now-ex-wife Sara's name tattooed on his neck pic.twitter.com/jJZLlnXa3q— Ben Axelrod (@BenAxelrod) January 10, 2017To every wrestling fan who has not watched WWE Network's The Last Ride, the documentary fittingly portrays the massive impact that The Undertaker's wife Michelle McCool has had on her husband's life. However, long-term fans know that she wasn't always the "lady love" in the Phenom's life.Before The Undertaker started a relationship with McCool, he had already been married twice previously. At one time, he was very much in love with his second wife Sara, as evidenced by the famous tattoo of her name that The Undertaker had on his neck. Getting a permanent tattoo is a painful process, especially when you get it on your neck as the skin there is much more delicate than, for example, your arm or thigh.The Undertaker decided to get the tattoo of her wife Sara's name on his neck. This was in the early 2000s when the two started appearing on WWE programming together with The Undertaker portraying a more humanized version of himself. Unfortunately, the relationship didn't last, as the two divorced in 2007. The Undertaker went on to replace his neck tattoo with the names of his two daughters.