While raising a child entails the good, the bad, and the ugly, it is arguably one of the most fascinating things in life; many parents would likely agree that there is no other feeling like watching your little bundle of joy grow.

And as they grow, they go through numerous stages, each more challenging and heartwarming than the last. Take an infant, for instance; though everything’s new and likely unfamiliar—even if you’ve had a child before, some things might still be a first with this one—such an age marks the beginning of a lifetime full of love (and a time full of diapers).

The toddler years bring a completely different dynamic into the household, as they start running around, throwing food, and testing the limits of any pets with ears big enough to grab onto them. And while some parents would love to go back to the time their little ones were toddlers, surveys show that the most fun time for moms and dads was when their little hell raiser was five years of age.

One of the reasons for five being parents’ favorite age was the fact that that’s when kids start to communicate properly and develop a good sense of humor. (You can find proof of that by scrolling through this list or the previous editions of the best parenting Tweets of the month.)

According to the survey, the most difficult time for parents to bear is when their kid is between 10 and 12 years of age.

While you may find it surprising that children as young as five are considered fun because of their sense of humor, they actually start to try to make people laugh at quite an early age.

According to associate professor of speech and communication at University of Bristol, Yvonne Wren, during the first few years of their life, kids' humor is of a physical and visual nature, which is why they can giggle like crazy at something as simple as “peek-a-boo” or silly faces.

The more verbal kind of humor that follows the “peek-a-boo” stage is often based on incongruity, which calls for understanding pretense and using one’s imagination. “They need to be able to come up with the ideas for something which is not true or cannot be real as a basis for developing the joke,” Wren wrote for a piece in The Conversation.

“They also need to understand that context is important—that what you say can have different meanings depending on when and where it is said,” she added. “And children need to have sufficient vocabulary to be able to express their imagined ideas and to describe the context when they would occur.”

Yvonne Wren continued to explain that once children realize that spoken words are not necessarily true and can be made up, and that they can have double meanings, they become able to tell a simple story—”they can use language to create incongruities in the form of puns and ambiguities which cease to confuse and start to amuse.”

While some five-year-olds’ jokes come at their parents’ expense, the latter shouldn’t be too upset about it; it doesn’t necessarily mean that their kid doesn’t like them and can actually show that the little one has a rather high IQ. A study carried out in Turkey found that intelligence and humor ability are highly correlated constructs.

According to Psych Central, the somewhat innocent tone of kids’ jokes tends to change before they leave elementary school, and by the time they are in grade four or five, boys and girls tend to laugh at jokes that are very different. Ten year old boys, for instance, tell jokes that are physically violent and sexual, while their female counterparts refer to humor that’s less physically but more verbally aggressive; likely because the latter have, on average, better verbal skills.

Whether it’s because of their little one’s sense of humor or other reasons, the majority of moms and dads—roughly four-in-five of them—find parenting to be an enjoyable and rewarding experience. This was revealed by a survey carried out by Pew Research Center, which also found that for many of them, it’s a rather stressful and tiring experience, too, which only proves that parenting indeed entails the good, the bad, and the ugly.