Six other titles have been won this year by the 31-year-old but compatriot Sloane Stephens upset her in the semi-finals of the Australian Open and Sabine Lisicki stunned her in the fourth round of Wimbledon.
"You know I'm not there yet with the way my year has gone," Williams told a small group of reporters on Monday at the Rogers Cup where she is the top seed.
"Everybody is like 'You've had a good year and I'm like, who?"
Williams said she is not satisfied unless she wins every big tournament that she enters, particularly the slams which account for 15 of her 53 career titles - a significant percentage.
"That's me," she said. "I work really hard to do the best, especially in grand slams."
This season, however, her form at non-grand slam events has been dazzling, proof that she is as hungry as ever.
From 2005-2010, seven of Williams 12 titles came at the grand slams. Since the start of 2011 only three of her 16 crowns came at the majors.
"It's more or less evening out, but I am okay just winning grand slams," she said. "What makes tennis beautiful is the small tournaments that make you as a player and make you win the grand slams."
"I was talking to (my sister) Venus the other day and I said I am never going to stop," she said.
"I just love this sport so much and we were just practicing. It's just so fun. I'm having more fun than I have ever had."
Williams said she was thrilled to see former number one Martina Hingis return to doubles play.
Hingis launched her comeback last week at the Carlsbad Open with her partner Daniela Hantuchova, reaching the second round.
She and Hantuchova will also play in this week's Rogers Cup.
Serena and Hingis - who were once bitter rivals - got to know each other better over the past year and half while Hingis was coaching at the academy owned by Williams' coach, France's Patrick Mouratoglou.
"It's great," Williams said. "She's so good and has great hands and sees the ball so well and she's fun.
"It's really kind of cool."
"I kind of am waiting for her singles comeback, but I'm not sure she will," added Williams, who will play either Italy's Francesca Schiavone or South Africa's Channelle Scheepers.
(Editing by Martyn Herman)
