Fatigue and my changing behavior

In my youth, whenever I was particularly tired, my fatigue manifested in a propensity to laugh too much and say bizarre things that I didn't always understand. In short, if I was tired, I appeared tipsy. Today, I've lost the ability to laugh when I get tired. Instead, I just spout strange statements that I still don't understand. In addition, I've noticed a mis-use of vocabulary and also a higher chance of saying things without thinking, which alternates with a moody silence. I'm not sure which of these is the worst.

Sleepdriving, by Grand Archives.