One of my favourite aspects of parkour is that it helps find joy and beauty in the simplest of things, in the case of parkour this is through human movement which is available to anybody which it why it so easily breaks down any barriers of class or wealth, race or gender by practitioners.
One aspect that I most enjoy on a similar note, when training alone, is simply shutting out the world with some music (of any description, gentle or engagingly upbeat) and focusing on my movement. I enjoy this greatly when balancing along rails: walking backwards and forwards in populated areas along a rail requiring some level of focus to manoeuvre with the buzz of life around actually helps to emphasize the beauty of parkour. The feeling when training alone amidst a sea of people deep in chaos is a surprisingly liberating feeling. This to me is bliss, finding beauty in the simple act of balance.