What is the secret to a 'successful' marriage?

This morning, I woke up with a thought. This was not the first time I thought of this, but I decided that since I am making an effort to keep my blog going, I will ask you about it too.

The question is: What is the secret to a successful marriage?

I guess one of the things I am expecting if anyone comments on this is their definition of successful in the first place especially as it relates to marriage. I also believe that there might be some differences between different cultures in this regards too.

So lets have it. What do you think? I am all ears......