One must enter into each and every endeavor with a clear and calm mind. This tranquil mindset is called meikyoushisui (明鏡止水) in Japanese which translates to "clear and serene." When we are agitated or upset that "forces" us out of balance and with out this balance there is no harmony. Without harmony, there can be no Aikido.
Our art requires us to see the "bigger picture." With this expanded horizon we realize that our partner is in pain and thus is in need of compassion. With harmony we are able to choose not to destroy them but to instead help them.
The first step within any confrontation is harmony. First with yourself then with your partner.