Barack Obama of course gave an important speech Thursday night with far-reaching ramifications outlining his "Executive Action on Immigration". Of course the President displays a multitude of body language signals throughout this speech - yet upon watching it, we see a nonverbal tell before he even speaks; and as he is walking up to the lectern - one particular nonverbal dramatically jumps out.
Very briefly, during the 0:01 mark of the above video (and captured in this image), the expression on President Obama's face is very clearly one of regret.
We don't know precisely why he is thinking-feeling regret - perhaps he wishes he should have taken this action six months ago as it may have positively affect the huge losses democrats suffered in the elections earlier this month. Maybe he regretful in his anticipation of what republicans will say and do. Maybe he is feeling regret in that he felt he must take this action rather than waiting for congress to pass bill (as he said in this speech). We can go on and on with specific speculation - yet in this second before he began the speech the President felt regret.