|Maxed out the Stress attribute|
|Unlocks once Stress reaches 100|
The 'Twitchy' achievement is gotten by having 100 Stress points.
When getting this achievement, you REALLY should go ahead and go get the 'Stressed Out' achievement.
How to Get 100 Stress Points Edit
The easiest way to get 100 stress points is to start in New Orleans. If you have a save early in New Orleans, load that, and do every caper possible but fail everything, passing only the red obstacles/obstacles you have to pass. Never sleep, and purposely go out of your way to choose dialogue choices that add stress. Instead of sleeping, just raise your stress skills. If you have a lot of capers left in New York, do all of those as well. If you don't have many capers left in New York by the time you leave New Orleans, you may need to load from Peru or New York before New Orleans instead.