This is an impression of a "tough dog", as performed by entrepreneur whose determination is shown through gritted teeth and never failing optimism in the face of rejection, sleepless nights, and stress at starting a new company.
It's easy to give up. Retaining confidence, determination, and forward moving energy is super tough in the face of constant adversity. Rejection, business deals moving too slow, running out of cash, wondering when revenue is coming in, investors and partners beating on you, your staff is not working out and you need to fire them - the list goes on and on of things faced by new entrepreneurs.
But you can't give up. If you do, then you may never realize your dream of watching your company and idea flourish and grow. You need to learn that the world is going to constantly try to beat you down and you have to live with that, roll with the punches, and keep moving forward. There will be times where it will seem you've hit rock bottom, but only to fall even lower. You, the budding entrepreneur, need to expect this, prepare yourself, and keep saying to yourself that it will get better, and to drive towards making it better.
Because if you can't adapt, then maybe you shouldn't be an entrepreneur. You'll die of despair and never get anywhere. Know yourself before you embark in entrepreneurism.
Or...learn how to say:
GRRRR ROWRRR ROWRRR
It really works.