Over time, our vaccine cheat days start to add up. It might truly be innocuous for a few people to cut a couple of corners on occasion. But eventually, a series of flubs will allow exposures, which will in turn beget disease. Our shortcuts also signal to others that it’s okay to chill out when it is very much not.

Now is not the time to relax—quite the opposite. “We’re so close to the end that we should be extra careful right now,” Julie Downs, a psychologist and behavioral scientist at Carnegie Mellon University, told me. The problem is, our lapses don’t just slow us down. They set us back, in the same way that repeatedly opening an oven door will prolong the time it takes to bake a cake (and, at worst, make your delicious dessert collapse). Having made so much progress, we risk a lot with our impatience. And right now, we’re in serious danger of botching our grand pandemic finale.

The CDC can’t be expected to lay out every possible social scenario that a vaccinated person might encounter. But public-health officials do have the tough job of tweaking guidance based on new data on vaccine effectiveness. Wobbly rules are harder to communicate and follow; even CDC Director Rochelle Walensky seemed to waffle last week while discussing how effectively inoculations thwart infection and the risks of post-vaccination travel.