Amazon sells 1,161 kinds of toilet brushes. I know this because I recently spent an evening trying to choose one of them for the bathroom in my new apartment. Nearly an hour later, after having read countless contradictory reviews and pondering far too many choices, I felt grumpy and tired and simply gave up. The next day, I happily bought the only toilet brush the local dollar store offered.

Too many choices exhaust us, make us unhappy and lead us to sometimes abscond from making a decision all together. Researcher Barry Schwartz calls this “choice overload.” And it’s not just insignificant details like which brush to wipe the inside of the toilet with–having too many choices in our creative and professional lives can lead us to avoid making important decisions.

“As the number of options increases, the costs, in time and effort, of gathering the information needed to make a good choice also increase,” writes Schwartz. “The level of certainty people have about their choice decreases. And the anticipation that they will regret their choice increases.”

Understanding how and why we make decisions can perhaps help us make better choices down the line.

We make poorer decisions when we are tired. It’s caused by decision fatigue. The mind can only sort through so many options and make so many choices before it starts to run out of steam. That’s why impulse buys like candy bars and magazines at the checkout aisle in the grocery store can be hard to resist. We’ve exhausted all our good decision-making skills.

The same goes for our workday. Making lots of decisions not only exhausts us, it can put us in a fowl mood. A study out of Columbia University found that judges were more likely to give prisoners a favorable ruling in the beginning of the day and after a food break, than at the end of the day.

That’s why it’s important to make your most important decisions in the morning rather than at the end of an exhausting day when your energy has been depleted. The “sleep on it” idiom really does have clout when it comes to making big decisions.