Perfectionism is the unrelenting pursuit of reaching the highest possible standards and then still left wanting more. It is a heavy burden put upon one's self.
It ruins relationships because it's not enough for you to be perfect - you start paying attention to the flaws in others and wish those gone. Understandably, this is not going to end well.
Being lazy becomes a problem, an uncomfortable feeling grows that you should be doing something productive (thanks, Capitalism). The mind becomes restless.
The bed-fellow of anxiety, you feel that if you don't constantly achieve, you will fail. The fear of failure is crippling and pointless. If we don't fail, how do we learn and grow? As someone who used to be a leader at work, this became quite an overwhelming problem because I felt that my failure would fail the team and their failures would fail me.
From the excellent book, Less Perfect More Happy:
Perfectionists worry. They worry hard and they worry alone. They don't worry about the present; they miss out on that while they worry about the past and the future - the past expectations they haven't lived up to and the expectations of a future they might not fulfil.
This perfectly sums up the damage perfectionism can cause and how it can prevent living a fulfilling life.
I've stressed out and aged myself too much following this dead-end path. It's time to accept that good is good enough. We are mere pinpricks in this ever-expanding universe after all.