Depends on which "we" you're talking about. But in the US, these are rarely enforced, and then only against blatant lies that have substantial financial impact.
It's perfectly legal to mislead, confuse, shade, distort, bamboozle, trick, and distract. And you can lie outright if the lie is small. Or if it qualifies as puffery, which basically the kind of lie we have come to expect from people selling stuff.
For example, Shell can say "We care about the environment" and show pictures of frolicking wildlife. They aren't obligated to say, "but we care about profits more" and show some pictures of oil spills.
My favorite example is Airborne, a purported cold preventative that does precisely nothing. They lied in their advertisements for years and made fistfuls of money. After more than a decade somebody finally sued them, and eventually the FTC beat them down as well. The result is that they had to give some of their ill-gotten gains back, and now lie by implication rather than by direct false statements.
But that only happened because a) they were provably wrong, and b) they had enough money for class action lawyers to decide it was worth years of effort to take a whack at their money pinata. As long as your lie isn't provably costing money and provably false, you're basically golden.