In the extreme
Definition 1 of 2
Pro Tip 1/3Intensity Emphasis
Use 'in the extreme' to highlight extremely intense qualities or behaviors. 
His dedication to his job is punctual in the extreme.
Pro Tip 2/3Negative Connotation
The phrase often suggests a quality has moved beyond normal to potentially negative. 
Her frugality is economical in the extreme, bordering on stinginess.
Pro Tip 3/3Subtle Critique
Can imply that an extreme degree of something may not be entirely positive. 
His approach to problem-solving is cautious in the extreme.