* Subjectivity: What's "the worst thing to do" is highly subjective. It depends on individual values, beliefs, and priorities. Some people might find watching cartoons at 18 frivolous, while others might see it as harmless fun or a way to de-stress.
* Lack of Evidence: There's no scientific evidence proving that watching cartoons at 18 is harmful. It's not like consuming something dangerous or engaging in illegal activities.
* Individual Differences: People mature at different rates. Some 18-year-olds might be ready for more "adult" entertainment, while others still enjoy cartoons. There's no universal standard for what's appropriate at a certain age.
It's important to remember that judging someone's interests or hobbies is usually based on personal biases, not objective facts.