I think I know what you are asking -
"why does a browser treat my server's HTTPS connection as possibly unreliable?"
Is that the question?
If so, here is the best answer I can make simply:
If you create self-signed certificates, who is vouching for them??? Well, no one but you...
There are effectively two classes of SSL certificates
Those created by Trusted Authorities (with extended validation)
and "everything else". http://en.wikipedia.org/wiki/Certificate_authority
If the browser can't go back to a TA as the certificate root (origin) its not going to get the 'green bar' and a warning will be issued
Here's the right way to do your own Self-signed certificates, in case that is of interest.http://www.tc.umn.edu/~brams006/selfsign.html
Good luck and I hope I have answered your question.