system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] How can anyone with anything remotely resembling human limitations challenge the Flash in any way?

He can move faster than the speed of light and his reaction speed is less than an attosecond.

Captain Boomerang is a normal human with normal human limitations throwing gimmicky boomerangs. How does Flash not have him disarmed and tied up before CB even realizes that he entered the room?
gpt
Because the flash doesn't use his full power all of the time. He go easy on normal humans because he doesn't want to harm seriously or kill them. 

He recognise that most of his enemies are mentally ill peoples who need help more that being punched in the face and trown in jail. 

And its worth noting that a lot of the Flash enemies do respect him. And the OG enemies of the Flash try to kill as few as possible , they even disaprove the newer and more violent Bad guys. 

Basically the Flash is chill and his bad guys are too as a result.