Think of it like a child. If you baby him 24/7 and overprotect him, he's either going to grow up as a spoiled little brat or a pansy.
Occasionally he needs some tough love.
Thats why my break in period consists of ripping through the gears almost to redline.
Modern cars are built with very fine tolerances, they don't need to get acclimated to anything. These aren't delicate pianos. Why do you think Ferrari runs each car around the Fiorano test track before they send them out to customers? Or why Nissan dynos each R35 GTR motor before they put it in the car and ship it out.
Babying your car only makes it slower! (note this theory is not and most likely can not be supported by concrete evidence, but I don't give a sh!t)
Cheers