Maria Sharapova says she never wanted to change herself to fit others' expectations.Jemal Countess/Getty Images for TIMEMaria Sharapova, 39, says her intensity was a key factor behind her success.The tennis player said she wasn't affected by what people said about her as she was fully committed to her sport."But 'pretty tough' was my mentality, and I didn't apologize for it," she said.Maria Sharapova, 39, says her intensity was key to some of he…