After watching This clip, I can point out a few things I noticed about how deeply upset Obama was when some of his former black supporters chanted for him to 'keep his promise' about increasing global AIDS funding. In the poker world, we call these 'tells'

Between 0:20 and 0:35 Obama is as close as i've ever seen him to completely blowing his top. 

 

The following expressions or 'tells' as poker players call them reveal the signs of a mad man in the making:

 

-1. The disruption of his tele-prompter reading is a sure sign that  the chanting got to him.

-2. He says 'excuse me' no less than 5 times

-3. He thrusts his upturned hand out to towards the protesters in frustration

-4. The hard swallow at 0:23

-5. Wagging his finger

 

-6: Sucking and smacking your lips is known as 'pacifying behaviour'

-7. you can clearly see the crease between his eyebrows as he frowns / furrows angrily

-8. He appears incoherent when saying 'you guys have made your point, lets go'

-9.Head tilting

 

-10. The smug expression on his face when his supporters respond with a chant of their own. When smirks at his protesters, I am reminded of a teacher's pet sticking their tongue out at the class as the teacher praises them.