What do you think of this cover letter?

It is terrible. This is not the time to show off your "quirky" humor nor to discuss your past depression. Stick to praising the company, outlining your qualifications as they pertain to the job and tell them how you believe you are the best candidate for the position and request a meeting with them at their convenience. A cover letter like the one you posted will end up in the trash can in 99.9% of companies you apply to. They can discover your quirky humor once you get the job.