I mean serious regret that for some people can be debilitating. (remonline.com)
My other prediction is that whatever team gets him will have serious regrets at one point, but that's true of just about every free agent. (sbnation.com)
Our administration made some missteps, for which they have expressed serious regret, that have had negative and regrettable consequences, not the least of which is the decision of Professor Hawkins and Wheaton to part ways. (firstthings.com)