When you use Scrum, most people think it's not compatible with Process Improvement Models like CMMI.  At my work CMMI is used by the testers for structured testing. So we have a Lova and Hate situation.

Well, the following article proves that we are wrong and the there's a Love and Marriage situation: http://www.stsc.hill.af.mil/crosstalk/2010/01/1001Glazer.html

(Thanks to my colleague Tom Vercauteren for the link)