Optimism is protective--we all know that confident people have a leg up in realizing their ambitions, and "fake it till you make it" can often be a successful strategy. Plus, looking on the bright side generally feels good. Scientists even tell us that realism is correlated with higher levels of depression.

But let's be honest: Sometimes all of us can take the rose-tinted-glasses routine too far. Just hoping things will turn out well stops us from making tough choices, believing the best about others can get you taken advantage of, and a failure to look at the world as it truly is can be harmful to both your business and your personal life.

In what circumstances are many of us guilty of wearing blinders? Great crowdsourced answers to this question recently appeared on question-and-answer site Quora when someone wondered "What is an example of something true that nobody generally wants to admit?" While some responders had particular axes to grind (it’s true that U.S. drug prices are radically higher than elsewhere in the world, for instance, and maybe a gamma ray burst could destroy earth, but those aren’t really things you can act on tomorrow), many more offered healthful reality checks that most of us could benefit from, including:

1. Most people don't know what they're doing.

Well, at least you’re not alone. According to writer Amit Banerjee, many, many people are stumbling around in their careers and personal lives, bumbling into their next relationship, job, or major life change. "Most of us actually don't know what to do with our lives," he writes. "We are just figuring something out, and to some extent, pretending on the way."

Engineer Kris Rosvold words this slightly differently: "We, almost all of us, are faking at 'being adults.'" While student Sri Teja puts a positive spin on this tough truth: "The people you look up to are just as nervous as you are."

2. Looks matter.

Is it fair? No, but it has been scientifically proven again and again. So there’s no point in denying reality, student Dania Faruqui suggests. At least that way you can manage your own tendency to judge a book by it’s cover and make clever decisions about how you present yourself.

3. No decision is a decision.

Making tough choices is hard, but you can’t avoid them. Not deciding has just as many consequences as any other alternative. "You have to make decisions all the time," developer Taalai Djumabaev reminds people in his response. "Even postponing a decision is your decision. Many people just wait until they have only one option and think that they can now make a decision, yet, it has been already made." 

4. We're the same as the crazy people we read about in history books.

"Everyone looks at the past and recognizes flawed human beliefs and behaviors, but no one realizes future generations will do the same with us," investor Chuck Gafvert points out. Culture changes, technology advances, but intellectual errors and human frailty remain constant. The exact content of our mistakes will certainly be different, but rest assured this generation is doing something ridiculous. 

Or look at this one another way and you’ll see that it’s hubris to assume we’re safe from repeating some of history’s stupider moments. "Think 'XYZ from the past could never happen today; this is the 21st century!'?" asks entrepreneur Dan Deceuster. "It can." Be aware that something you believe or do is likely to be looked on as ridiculous by history and stay humble (and vigilant).

5. Suffering is real, constant, and random.

OK, you probably know this intellectually, but for our sanity (and our mood), most of us go through most of our days not actively thinking about how much suffering is going on in the world at any given time. And the worst part? That suffering is largely random. "The circumstances of our births are completely random," PR professional Peter Lenardon reminds us. "Everyone is just a consciousness that came online in a body somewhere. I got 'white middle-class guy in Canada.' Someone else got 'little girl in a brothel.'" 

What’s the point of facing this terrible truth? It might put your own problems in perspective (or even motivate you to make the world a slightly better place). "You should keep it in mind that your worries may not be the only problems in the grand scheme of things," writes founder Ishan Rana. "Just the realization that millions of people would do anything to see their kids sleep for a night in your bed, or wish that they could eat those vegetables you just trashed, would do our planet a world of good." 

What would be your answer to this Quora question?