According to Wharton management professor Sigal Barsade, a perk that's "tied to the values of the company, … a living instantiation of the culture, then it can have deep symbolic meaning." Barsade points toward bereavement days for a pet's death as an example, which can be "a great representation of a culture of companionate love—that is, affection, caring and compassion," and possibly very representative of a company's emotional culture.

Candidates may not be aware of the stakes behind such perks, but according to the report, the top one percent of talent at a company can be responsible for 15 to 20% of "value-added," which means that a company will go pretty far to bring in that top talent. But the wrong gesture can be seen as a sop, rather than something that's actually meaningful in terms of improving the employee's life.

Although most employees surveyed say the perk they'd most like is unlimited paid time off, employees themselves often fail to realize the reality that they probably don't use all the paid time off they already get. Yet studies have shown that such a policy actually does attract higher-quality workers, who not only are happier but produce better.

Still, companies have to beware sending the wrong message with perks on offer, since Barsade points out that "if you sense you are being coerced into staying at work longer and don't want to do that, then having all these things on site may well be viewed negatively."

Companies should be asking employees directly in surveys and focus groups how they feel about what they're offered, and not relying on anecdotal evidence—particularly since they can be exerting other pressures, subtle and otherwise, on employees by sitting on pay increases, freezing benefits and bringing in gig workers—tactics that could negate any benefit they might otherwise derive from offering people perks by delivering an underlying message of not caring about, rather than valuing, the people who work for them.