"We/you need to be more careful" is often a phatic expression, a way of ending the conversation while saving face, rather than an actual directive. Because the

"We/you need to be more careful" is often a phatic expression, a way of ending the conversation while saving face, rather than an actual directive. Because they don't want you to be more careful. They just want you to make sure you respect their time and their timeline, and check that you're not deliberately being an asshole who's fucking up their job that they don't understand, because of some sort of attitude problem. It's social ritual.