“Aim for the stars and maybe you’ll hit the treetops” was always the kind of advice I was given when I was younger. But extremely high expectations of oneself is not always a great thing. We have to learn that we’ve got limits. Some are physical, some are mental, and some are cultural:

The problem with placing too much emphasis on your expectations—especially when they are exceedingly high—is that if you don’t meet them, you’re liable to feel sad, perhaps even burned out. This isn’t to say that you shouldn’t strive for excellence, but there’s wisdom in not letting perfect be the enemy of good.
A (now famous) 2006 study found that people in Denmark are the happiest in the world. Researchers also found that have remarkably low expectations. And then:
In a more recent study that included more than 18,000 participants and was published in 2014 in the Proceedings of the National Academy of Sciences, researchers from University College in London examined people’s happiness from moment to moment. They found that “momentary happiness in response to outcomes of a probabilistic reward task is not explained by current task earnings, but by the combined influence of the recent reward expectations and prediction errors arising from those expectations.” In other words: Happiness at any given moment equals reality minus expectations.
So if you've always got very high expectations that aren't being met, that's not a great situation to be in
In the words of Jason Fried, founder and CEO of software company Basecamp and author of multiple books on workplace performance: “I used to set expectations in my head all day long. But constantly measuring reality against an imagined reality is taxing and tiring, [and] often wrings the joy out of experiencing something for what it is.”
Source: Outside