Title/plot could be interpreted to mean "Don't sweat the small stuff, and it's all small stuff." But there's actually a fair bit of big stuff happening (absent parents, marriages in jeopardy, suicidal thoughts). You can also look at it as saying "Every person has his or her struggle," though that seems to go against the grain of several of the plots' resolutions. Still, parent-child relationships are valued, as is frank communication.
A fight between adult men at an elementary school is played for laughs due to its incompetence. A dead body is a plot point; it's carried around and discussed. One person falls from a rooftop but is miraculously OK. Arguing/confrontations.
A fair amount of sex talk. An extramarital affair is a plot point, with frank descriptions of a sex act performed (it's extensively discussed, including in front of children). One character angrily demands to see another's genitalia. A crude drawing of a penis is a plot element.
Frequent strong language, primarily "f--k." Also "s--t," "bulls--t," "d--k," "c--k," and more. Sexual descriptions.
One character wakes up in his car after having passed out drunk there the night before; he throws up. He later smokes a cigarette on school grounds (which is called out and objected to).