Cultivating self-compassion

I'm studying an online course with FutureLearn called 'Mindfulness for wellbeing and peak performance', which is fascinating stuff. I've studied mindfulness before, but never with this particular focus.

We have reached the part where we try to cultivate self-compassion. Why is it so much more difficult to be kind to ourselves than to other people? I shall be dripping this bit of philosophy into the classes I teach over the next little while and including the following affirmation:

May I be happy;
May I be well;
May I be peaceful;
May I be safe.

Try it. What's the worst that could happen?