What do these quotes have in common?

‘Why did I enjoy it? I used to play with it. I used to do whatever I felt like doing – it didn’t have to do whether it was important for the development of nuclear physics, but whether it was interesting and amusing for me to play with.’ – Richard Feynman

‘Be inspired, enjoy your job, keep learning and never forget to play.’ – gskinner

Why not be great? [..] Many people will have to answer that question by saying, “I spent my time waiting, whining, worrying, and wishing.” Because that’s what seems to be going around these days. Fortunately, though, not everyone will have to confess to having made such a bad choice. – Seth Godin

“We’re building a badass team. Honestly, we’re bringing together the best developers, no question about it.” – dougmccune