Here's why:
* Nettles are prickly plants: Touching them causes a stinging sensation.
* Grasping them directly: You must face the discomfort head-on to deal with them.
The idiom suggests that by taking immediate and decisive action, you can overcome a challenging situation, even if it's initially unpleasant.
Here are some examples of how it's used:
* "I've been putting off telling my boss about the problem, but I guess I need to grasp the nettle and just tell him."
* "The company is facing a difficult financial situation, but the CEO is determined to grasp the nettle and make the necessary changes."
In essence, "grasping the nettle" implies a proactive approach to dealing with adversity. It's about facing the challenge head-on, rather than avoiding or delaying it.