Why is it that when someone makes a mistake we say “it’s only human” to comfort them?

It’s because on some level we all know that it’s a difficult thing being a human in this world. 
The human experience is imperfect, painful at times, and very often challenging. A part of the experience of being human means you are capable of making mistakes and at times you will be wrong. Even when you are not at fault at all for difficult situations – we may believe we are the only one having this experience and so push other people away rather than invite them into our hurting heart. 
We’re often immersed in our triggers when we are dealing with a stressful circumstance. When you add resentment or guilt to that, you are likely to feel alone in it. And unfortunately, with the medical model focus on “fix” over “feel” and the pressures to look young and feel good all of the time that we are often exposed to via media messaging, our feelings of sickness as an abnormal state that “shouldn’t” be happening may increase. At times, when we, or a person we love, are struggling with health issues we may come face-to-face with feelings of complete inadequacy and deep disappointment as things don’t go the way we deeply wish them to. If we feel alone in our journey, we may end up in a cycle of anger and self-pity, and that can feel like a trap with no way out. 
When people feel that they have failed, they disconnect from the world rather than see the common experience. Shame and inadequacy rule the roost and our inner eyes focus only on our personal shortcomings. We become immersed in feelings of insecurity and self-loathing as if no one else exists, it’s like all our thoughts are driven by an emotional layer we can’t quite lift out of, as if we are the only one who has ever been proven wrong, or humiliated, dumped, or sick, or losing someone or something important to us. 
Remember, feelings of inadequacy are universal; the pain I feel in difficult times is the same pain you feel in difficult times. 
Suffering is a shared aspect of being human. The situation is different, the degree of pain and the triggers are unique, but if you focus on what you have in common with others, you will see that you are having an experience of human hurt, and that is universal.
Compassion literally means “to suffer with.” This means that despite living in a culture that tends to value stoicism and logic, a culture that teaches children times tables instead of empathy, we tend to forget the most important thing for us to remember – that we are not alone. 
Self-compassion is magic. Not the wand or crystal kind but the kind of magic that reminds us that we can heal the heart with our mind. 
When we finally stop asking “Did I do enough?”, “Am I good enough?”, when we finally give up our expectations that things will look like this or that, and if they don’t then we have failed … then we will find an inner wellspring – and at our center – a fountain of unconditional kindness. And it is in this place that we will feel more secure, accepted, celebrated. You will see the beauty in life in yourself and in others. The neurotic ego cycles that all humans experience, swinging between self-serving distortions and the harsh inner voice, will transform into music and this music will be the soundtrack to a deeper dance with Self.  
Good is good enough. Some things are out of our control. All hearts know pain. 
And… Suffering can soften your heart. 
Let go of needing to see yourself as perfect and remember, you’re human.
Kia Ora,

(In New Zealand “Kia Ora” means ‘Hello, Goodbye and Thank You’)