Since Henry was born, one thing I've tried to do with him is help him label his emotions. It's something that we take for granted as adults. We cry because we're sad, we yell because we're angry, we pout because we didn't get our way. We usually know how our actions and feelings are related. Yet, even as an adult sometimes I can't explain what I'm feeling. Sometimes I just get out of sorts for no reason. Or I start crying (thanks hormones) with no explanation. So, if I as an adult can't even always figure out my emotions, I can only imagine what it must be like for someone who is new to the world.
When Henry starts crying because he falls down I will help him verbalize his tears, telling him that he's hurt and/or scared. When he is screaming and crying while I try to put him in his car seat, I will vocalize that he is angry with me and doesn't want to go in his chair. I also explain to him that although he doesn't want to ride in his car seat, it's the only way to be safe in the car. When Henry throws himself on the ground in the evening, I tell him that he is upset and tired. What I try to avoid in all these instances is telling him "it's okay" or "you're okay."
Why do I do this? Well, in addition to helping Henry label his emotions, I want to validate them. He's upset for a reason. In his world everything isn't okay and he isn't okay. Even though those statements come from a good place, one of reassurance and care, they can be dismissive. Telling him "you're fine" says "I don't understand your experience," "what you're feeling isn't valid," and "there's no reason to be upset." Even if, in my adult mind, there is no reason for him to be upset, he feels something and his emotional reaction is justified in his eyes.
Although I slip sometimes, rather than say "it's okay," I aim to help him understand his experience. I label his emotion, explain the situation (if applicable) and let him know that I am there for him. Whether I hug him, hold him, nurse him, or tell him with my words, I want him to know that, even in the depths of his emotional distress, I am there. I see him, I hear him, I am there. I will sit with him, talk to him, and help him work it through. It may not be okay in the moment, but together, hopefully we'll get there.