When someone says "don't cross me" or "don't mess with me," they are issuing a warning to others, emphasizing that they should not take actions or behave in a way that would provoke a negative or confrontational response from the speaker. These expressions are used to assert authority, establish boundaries, and indicate that the person is not to be underestimated or taken lightly.
Essentially, it is a way of telling others to avoid doing anything that could potentially lead to conflict, opposition, or negative consequences from the person making the statement. It implies that the speaker is confident in their ability to defend themselves or handle any challenging situation that might arise.
It is essential to take these warnings seriously, as they often indicate that the person is not willing to tolerate any form of disrespect, interference, or harm. Ignoring such a warning may result in unpleasant or confrontational interactions with the individual, as they may feel compelled to protect their interests or maintain their boundaries.