Even after many years, many of us continue to practice harshly. We practice with guilt, as if we're going to be excommunicated if we don't do it right. We practice so we won't be ashamed of ourselves and with fear that someone will discover what a “bad" meditator we really are. The old joke is that a Buddhist is someone who is either meditating or feeling guilty about not meditating. There's not much joy in that.
Maybe the most important teaching is to lighten up and relax. It's such a huge help in working with our crazy mixed-up minds to remember that what we're doing is unlocking a softness that is in us and letting it spread. We're letting it blur the sharp corners of self-criticism and complaint.