what is ethics?

For me ethics are the guidelines that tell us how we should act according to the situation we are on, naturally this is going to be differnet for everybody,not everyone is going to act a certain way or just the way you as a person think they should act and this is because of how people were raised by their family.This is something that affects and can be easily seen thanks to your own definition of what is good and what is bad as well as how varied is this definition comparing it whit the definition of someone else.
For example it could happen that for me taking care of somebody else`s stuff when i`m using it is something that i ought to do so it would be something ethical to think about it however for someone else that could be something not worth the effort so why bother taking care of that if that isn`t even mine in the first place?,why should i care about that? that is not important at all furthermore that particullar way of thinking could be ethical for that person.