Tears an evil? Maybe fake manipulative ones. Alas, tears and I have been very good buds for the past few months. My dad used to say of me, "Yes, her water always was close to her eyes."
I refer to crying as soul-rinsing. Our bodies are energy, and sometimes the best way to move out stuck energy is to have a good cry. It was quite common during yoga teacher training for someone to start sobbing on their mat. Yoga moves a lot of energy, and sometimes the only way to let go is through tears.
One way to inspire tears is watching a sad show or movie (or alas, reading the news these days). I would offer for that purpose "The Art of Racing in the Rain." It's an excellent movie that left me sobbing.
If you are with someone who is crying... let them cry! Let them have their flow no matter how uncomfortable it may make you, no matter how driven you may be to try and fix the situation.
We cry for many reasons, and no reason. It's all OK. Tears are cleansing and holy.