What is the true level of danger when a SSL certificate is invalid?

Question

I'm relatively tech-savvy, but I'm no security expert. To my understanding, an invalid SSL certificate is only a problem if you're going to provide some sort of potentially exploitable information to a website and you are not sure that the website you're at is truly owned by the organization you believe it to be.

I ask because my workplace uses content filtering that makes every SSL cert invalid. The browser sees the website as originating from the content filtering server on the network rather than the actual server the website is being served from. I'm tempted to simply turn off certificate checking altogether in my browser (Firefox) because it's not doing anything for me other than creating hassle, but I wanted to check to see if there's some facet of the issue I might be missing? I'm smart enough to ensure that the website I'm visiting is the website I think I'm visiting without the confirmation of the cert, so based on my understanding, I shouldn't have any problems.

Answer 1

The main problem, IMHO, is that your browser (or your client's browser) is always complaining about invalid certificates. If it happens once in a while, you go and check whether is an error or not. If it happens every time you stop checking. I mean, your information could be safe from sniffing because you're encrypting the communication channel, but you may be talking with a rogue server, and that could be easily exploited.