Anne's story is a celebration of friendship, imagination, creativity, hope, and finding family in unexpected places. Characters learn lessons from their mistakes, and Anne always tries to improve herself when her flaws are pointed out.
Anne's impulsiveness and enthusiasm lead her into scrapes of all kinds, but she usually means well and tries her best to learn from her mistakes. She's quick (in most cases) to make amends, though she can hold a grudge. She's also smart, imaginative, independent, hardworking, and creative; in other words, an excellent role model. Marilla and Matthew are loving (if not demonstrative) caregivers, and they parent Anne the best way they know how. Some characters can be flighty and/or spiteful, but they either learn the error of their ways or are clearly meant to be unsympathetic.
A few episodes find Anne lashing out in anger or stuck in mildly perilous situations -- walking atop a roof, for instance, or floating in a leaky boat -- but there's no real violence or danger. A key character's death is very sad, and an episode in which a baby is very ill is tense. Anne enjoys tragic tales of woe and imagines many of them. School discipline is stricter/more corporal in Anne's world than in ours.
Very mild flirting/romance between some characters. A teacher pays special attention to one of his teen students (which is less scandalous in Anne's time than it would be today but is still a little eyebrow-raising).
Drinking, Drugs & Smoking
Anne accidentally gets Diana drunk during a tea party due to a bottle mix-up.