Because that's likely their form of entertainment
They teach us that cartoons don't explain the world around us
They expect the teenagers to be more mature now, and the teens sometimes feel that they have outgrown cartoons.
The difference is the maturity and experience that an adult has. Watching only cartoons as an adult can result in a lack of maturity and experience whereas an adult watching cartoons as part of his or her entertainment shows responsibility and more maturity
because adults are older now they might still watch cartoons from time to time
I am not sure that they do. I am an adult, and I have never seen a show that told me that it was bad to watch cartoons. I still watch them sometimes, even though adults are a lot busier than kids usually, and we have less time to watch. But cartoons are still fun, and many adults still watch them. In fact, some cartoon shows are made for adults.
they are too old and watch ADULT shows.
Cartoons and children shows are a lot easier to understand they require less thought to understand them. Many adults look for something a bit more mentally or psychologically challenging. Add to that that there are some things that adults don't want children to see.
because their expectations are too high to have the perfect child
Some adults find normal tv shows boring and perhaps depressing (news etc.) They are trying to find a new source of entertainment and watch cartoons because they usually consist only happy and joy full things. In the other hand sometimes adults watch anime, which has shows that are meant to be watched by adults, so its normal.
because cartoons are not what an adult should watch unless he has kids. ___ On the contrary, many adults watch cartoons, and it is okay. That girl obviously doesn't like cartoons, but that doesn't mean no girls like them, or that they are any worse to watch than some of the "adult" shows that can be stupid too. There is no rule in adulthood that says you can't watch cartoons. I am an adult, and there are some cartoons that I enjoy watching.
cartoons are developed especially for children. The mind of adults is too advanced for any of that. Study shows, the older you get the more bored of cartoons you get.
I think it's because early cartoons were aimed at children, specifically. Cartoons nowadays have more adult themes and references than cartoons from the early 1900's to the 1960's. Those were cartoons from a more innocent era. People are more cynical and savvy now. There are plenty of cartoons nowadays that are aimed squarely at teens and adults. 'Family Guy', 'Futurama', 'The Simpsons', and many more, are written with an adult sensibility. I am not, in the least bit, ashamed to view these cartoons. In fact, I often reference them in everyday conversation. Despite all of this, I agree that there is a stigma attached to adults watching animated shows.