Improved cooling of ... You know, private parts.
Angel 1: Hey, what temp human will gave?
Angel 2:
36,6... Why you are asking?
Angel 1: Ouch! I designed those thingies thinking of 30,6 degrees
Angel 2: You WHAT??? Deadline in 2 hours! Ugh, fine. Here's a dirty hack: make them exterior for aircooling.
(turns out, those are testicles)
Angel 2: Truly dirty... Fine, send it as the final design and keep up a poker face, perhaps they won't notice the issue