"We're looking at ourselves in the mirror going: what have we done. You can't be that ruthless in the first half and be so toothless in the second," Youngs told reporters, struggling to explain how Scotland scored 38 points without reply before England snatched a draw.
"That's ultimately what we were. We thought the job was done and it was far from done. We were too loose, too flippant with the ball. Disappointing.
"There's going to be a lot of reflection on this one... I can't work out why it's happened but it has. We've got to figure out why and how we stop gifting teams momentum when you're completely in control of the game like we were."
Youngs acknowledged England's familiar failing in games over the last 12 months, but said the manner in which they collapsed in front of stunned home fans was frustrating.
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"It's so annoying. You're in complete control of the game to being completely out of control," Youngs added. "Had the game been tighter earlier, would we be doing some of those things? We absolutely wouldn't.
"Getting trapped into that circus of chucking it around, which isn't what we are about, that's disappointing. As a team, we have to nip that in the bud and be determined and strong enough to stick to the process."
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Toby Davis)
