system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does cough & congestion linger so long after the "cold" is long gone?

Why is it that when you get over a cold, the main symtoms of feeling "sick" go away but although you feel physically healthy sometimes the cough and congestion can last for weeks and sometimes months afterwards?  Thanks :)
gpt
Imagine you see a poisonous bug on the ground. You REALLY want to squish that bug. How many times will you step on it? Will you just tap it once real quick with your foot, or grind it in to the ground repeatedly to make sure it's definitely dead (even though the extra presses are probably overkill)? The second choice, of course - this is a poisonous bug! You want to be thorough! Similarly, when you get sick, your body doesn't just lightly step on the sickness. Your body hates being ill, and it will do everything it can to grind those germs it into the ground. This is why you may feel better fairly quickly after getting a cold (the bug is dead), but your body keeps coughing and congesting afterwards (to make sure that bug is actually gone for good).