I find it offensive: squarely in the baby-poo, vomit, etc category.
Edit: I'm referring to the background of the "alert" bar as well as the "welcome" box for not-logged-in users.
Pretty much duplicate of Thoughts on the new superuser logo and theme?.
To answer your question, I think the colour scheme garish, even hideous.
You probably mean for questions with accepted answer. I find nothing "offensive" about that color.