Former President Barack Obama said Wednesday that repeated Republican attempts to repeal his eponymous health care legislation are “aggravating” and would cause “real human suffering.”

“The legislation that we passed was full of things that still need to be fixed. It wasn’t perfect. But it was better,” Obama said, speaking at an event hosted by the Gates Foundation in New York.

“And so when I see people trying to undo that hard-won progress, for the 50th or 60th time,” he added, to laughter, “with bills that would raise costs or reduce coverage or roll back protections for older Americans or people with pre-existing conditions — the cancer survivor, the expecting mom, or the child with autism, or asthma, for whom coverage once again would be almost unattainable — it is aggravating.”

Obama said attempts to repeal the Affordable Care Act are “being done without any demonstrable economic or actuarial or plain common-sense rationale.”

“It frustrates. And it’s certainly frustrating to have to mobilize every couple of months to keep our leaders from inflicting real human suffering on our constituents,” he said.

“But typically that’s how progress is won, and how progress is maintained on every issue.”

Obama said progress “is never inevitable” and can “often be fragile.”

“It’s in need of constant renewal,” he said. “And our individual progress and our collective progress depends on our willingness to roll up our sleeves and work, and not be afraid to work.”