(Gerald Herbert/Ap Images )
As far as we know, there's only one "you" and time only moves in one direction.
But if, somehow, you could go back in time and meet your younger self, what would you tell them? Don't pretend you haven't thought about it.
Over on Quora and Reddit, there are a bunch of threads where people have shared the advice they'd offer. Read on for some of the most meaningful answers.
People don't care as much about you as you think they do
Quora user Sibell Loitz would tell her younger self not to take hurtful comments so personally.
"It's a waste of time," she writes." People are too selfish - therefore they do not spend much time in thinking about you and your behavior."
Psychologists call the general human tendency to overestimate how much other people are paying attention to you the "spotlight effect." In one study that illustrates the effect, people who showed up to a party wearing a Bob Marley T-shirt seriously overestimated how much the other party guests noticed what they were wearing.
Nothing lasts forever
Ujala Qasim shares a riff on the old adage, "this too shall pass." She writes:
"If you're sad, don't be hopeless, time heals everything. So just wait and see, it's just a matter of time.
If you're happy about something, just don't forget that the happy moments are going to pass anyway."
Forgive yourself your mistakes
"I’d probably start by saying to the younger me: Forgive yourself," writes Elizabeth Warren, US senator for Massachusetts.
"When my first marriage unraveled and when I started a new job and when I did dumb things, I beat myself up pretty hard. I look back now and realize that a lot of the challenges opened up new adventures."
Warren's observation highlights the importance of self-compassion, which scientists say can make you more successful. Instead of chiding yourself for being an idiot, try talking to yourself like you'd talk to a friend facing the same issue. Chances are you'll have a better chance of learning and growing from the experience.
(We can underestimate how important it will be to enjoy our work.Strelka Institute for Media, Architecture and Design Follow/Flickr)
Money isn't everything
"Do something you love," Bob Dunbar tells his past self. "Going to work every day just for a pay[check] and being unhappy is not worth it."
In fact, research suggests that we underestimate how important it will be to enjoy our work and overestimate the significance of how much we'll get paid.
That's not to say that money isn't important — but assuming you're making enough to live comfortably, having a good time during the day could be more meaningful than you think.