Age is something that many people hate, in short, people simply don't like the idea of them getting older and then receiving reminders of it once a year.
Celebrities are no exception to this idea and Emma Stone admitted that when she turned thirty-years-old, she felt "gloomy," for around a week. After that, according to Entertainment Online, she kind of realized that her age was a bittersweet moment for her.
What this might mean is that she kind of dislikes the fact that she's getting older, which would be the bitter aspect of it all. Then there's the sweet part, as in having a lot more knowledge since older people have more experience with the world that surrounds them than younger people.
Some of the important lessons that she's learned over her time on Earth, according to an interview Stone did with Vogue, are "Nobody knows what they're doing," and “It's OK if not everybody likes you." These are rather normal things to learn throughout life but are also important.
You see, if someone, especially a celebrity, never took the time to comprehend that not everyone will enjoy their content, then they will constantly be in a state of attempting to please someone who doesn't like them. If you look at the idea of no one knowing what's they're doing in life, you'd also see that it's normal. In general, it's safe to assume that thinking everyone around you has got it all figured out is a terrible thought. Many people focus on this and it's what puts them in a hole but it's also something that everyone learns, no matter what, unless they've never had a friend, ever.
Presently, Emma has not been working a ton and apparently even took a year off to reorganize herself. This was at the peak of her career but showed everyone one simple fact about her personality and possibly taught her another life lesson. That being that she understands how to put herself first at times due to the reality that if she didn't, she would burn herself out.
All in all, it seems like Emma Stone is someone who has a lot of lessons that she can teach her fans as she's gone through them in the past.