Fred Wilson has a classic post called Easy Come Easy Go. It is a short piece, but the idea behind it is that you shouldn’t depend on others for your success.
Depending on people, companies, etc. is never a good idea. You’ll always be waiting on someone, something, and won’t be able to work on your own schedule.
I’ve been burned many times while depending on third party solutions, APIs, App Store approvals, etc. As a side note, It’s actually something really attractive about Dwolla, as we have built our own infrastructure and don’t depend on the existing CC rail (as with everything there are pros and cons of doing things and there are also downsides to not leveraging existing technologies- but in this case to really change something you need to go a different route. You need to think differently).
There are some things it is okay to depend on other people/companies/solutions for- but in the end you should try to move away from depending on others and focus on depending on yourself.