The undefeated American was speaking during an open training session on Tuesday, ahead of his welterweight fight against the eight-division world champion in Las Vegas on May 2.
Mayweather believes he has identified some flaws in Pacquiao's style, claiming he takes too many chances in his fights, as illustrated when he was knocked out by Juan Manuel Marquez in December 2011.
"He fought very, very recklessly in the Marquez fight," Mayweather said in Las Vegas on Tuesday.
"I could have had the same type of career but my career wouldn't have lasted this long.”
Mayweather added that his last professional bout will take place later this year because he no longer boxes for enjoyment and that it feels like a job now.
"No. I don't enjoy it like I once did," the 38-year-old added.
"It is at a point where it is business. It is my job. I go to the gym. I train. I know what I have to do.
"There was a time when it was fun but I am to a point now where I am really over all of that stuff."
Mayweather believes the Pacquiao fight will be the biggest of their respective careers and features two future “hall-of-famers” going at it at the height of their abilities.
"He's a future hall-of-famer. I am a future hall-of-famer and we are meeting at the pinnacle of our careers," Mayweather said.
"From the matchup, it is going to be a very exciting fight.
"Our styles are totally different. I fight with smarts. Every move is calculated. Every move is thought about."
The welterweight unification fight will be the richest in the sport's history, with Mayweather earning about $120- million and Pacquiao about $80-million.