"Happiness is not a destination, it's a journey."
The above connects two complete sentences with a comma. I am assuming that it's grammatically wrong (strictly formal writing wise?).
You can make two separate sentences or use a semicolon (;).
* Use a semicolon when you want to make a bond between two statements, typically when they are related to or contrast with one another
Here is a great explanation by Todl
Last edited by JohnParis; 15-Dec-2011 at 15:56.