You're right. Big Bill isn't always!
But before assuming Word got it wrong, look at the reason for the green line - red = 'wrong' and green = questionable writing (either dubious grammar or bad style). Point the cursor at the underlined word and right-click; it often says something like 'Fragment, consider revising'. (This is my most common green-line offence; I usually do consider it, don't do it, and move on )
In your case I suspect you may have written quite a long sentence after 'How does it feel'; Word doesn't like long sentences (and it really hates it when it's anthropomorphized).