Stripe processed $1.9T last year. John Collison says there was never a moment where it suddenly felt like it was working. “Stripe never had a South by Southwest breakout moment.” “There were times when we'd be flicking the growth dial and saying, ‘Is this thing on?’” Instead, Stripe just kept getting bigger year after year. “It turns out you just, like, do that enough years, one after another, and you eventually get to $1.9 trillion.” “But it never felt like, ‘Oh my God, this thing is…