Quietly in June, Google added an option designed, no doubt, with imperfect human beings in mind.

In other words, designed for all 900 million of its Gmail users, give or take a few.

After testing it in labs since 2009, Google began wide distribution of an “undo send” option, allowing the hotheads, the drunk, the resentful, the misspellers, to yank back that Gmailed prose for up to 30 seconds.

“The cool new feature will alleviate, you know, some of the tensions that users experience when they send an e-mail sometimes,” a Google spokesman said.

Uh-hmmm. I know.

Soon after that announcement, a company called Delicious announced the launch of Dmail. It allows users to reclaim and destroy an already received e-mail message after one hour, one day — even one week.

Dmail, while not a Google product, is an extension available for download through the Google Chrome Web Store.

Still early in its development, Dmail, too, was built “out of a pain many of us have experienced,” wrote a Delicious spokesman. “We hope it makes life easier for you, as well.”

I get it. We’ve all done it, let our worst selves have their way at the keyboard.

Don’tpushsenddon’tpushsend don’tpushsend, oh, shhh, Ijust pushedsend.

So I’m not saying we shouldn’t keep options G and D in our back pocket. But let’s not rely on them, for a few reasons.

First, that e-mail you’re assuming is really gone, girl? Don’t assume it.

With Dmail, for example, messages sent to a receiver who also has Dmail appear in that person’s in box as normal. Those who don’t have Dmail will be sent a link to the “secure” message, which can be reclaimed at any point up to a week or longer.

Only the recipient and sender can read the e-mail legibly. If you believe that Delicious promise, Ed Snowden would like to have a word with you.

The team hopes to expand the application to let users set self-destructing timers on other types of documents, such as PDFs.

OMG.

“Some people may appreciate the greater sense of control that Dmail provides,” said Thomas Claburn, an editor at San Francisco-based InformationWeek, a publication directed at business IT executives.

“Mind you, it isn’t really actual control. Anyone determined to get around the system can do so by taking a screen shot.”

The screen shot reality is painfully true, as well, for nondisappearing acts such as Snapchat, so please have a conversation with your teenagers.

“The advice I give my kids is, ‘Don’t do anything online you don’t want to see on the cover of the New York Times,’ ” said Claburn, the father of two teenagers.

“It’s been a long time since I’ve said anything stupid because I’m very careful about it.”

Security issues aside, I worry that such “improvements” will take our Internet civility quotient down yet another notch, assuming there’s even an inch deeper to plunge.

These options give us too much leeway to be nasty to each other. “I know I said it, but I took it back!”

Which brings me to my final point before I step down from my soapbox. The mercy of “undo send” aside, we live in a far bigger world than e-mail. It’s a world of voice-to-voice and face-to-face dialogue where we, often understandably, feel frustrated or mad as hell, or we’ve had one too many, or we are paralyzed by fear and we say things that we regret, but we can’t really ever take them back.

All we can do is apologize and try to do better. And maybe keep a private journal instead.

Very therapeutic, I assure you.

“Ultimately, it’s your responsibility to be a decent person, and technology is not going to save you from that,” Claburn said. “Remember there is a person on the other end of what you’re sending. Use that to guide you.”