Which one is correct?

I see the website says Britney Spears sucks, or I see the website saying Britney Spears sucks?

By the time you realise you lose that many cos you never care about those you once have, it's too late.
Or
By the time you realise you lose that many cos you never care about those you once HAD, it's too late?
Or any correction needed?

Thanks.

And also
What I want is to take a shower or what I want is take a shower?

Why it's "What you need to do is leave" not "what you need to do is to leave"?

Thanks.

I see the website SAYS Britney Spears sucks. (the verb "saying" always has a form of "is" in front of it; it does not stand alone)

....once HAD....

What I want is TO take a shower.

"Leave" is being hypothetically substituted for "do", which already has "to" in front of it; no need to say it again.