I've watched it sparingly over the years.
I've never really watched any series of it fully, bar one.
Big Brother 9 (UK) was a really fun series, and I watched that for it's highlights every day.
That series happened to have some pretty interesting characters.
A lot of the time it's just idiots and arseholes, and it's exceedingly repetitious.
BB9 had just enough variety and character that it remained interesting throughout.
And I never watch Celebrity Big Brother. I might watch when the contestants go in to see who they have on, but beyond that, it's also pretty boring.
Just ends up being a terrible ego-contest.