Bush is not Reagan, and this is not 1980.
Again, Reagan was almost 20 years older, had been shot, put in a full days work and still was ready for the challenge in 84. No excuse for the President. The President looked more rested at the end of the day on 9/11 (probably the most difficult and trying day of his administration) than he did tonight.
...or 1984.
Besides, it was easy for Reagan to be relaxed. Alzheimer's does that for you.