Answer:
I can ruin your day, or darken your life. And while I'm expected, I'm never alright. I'm bad for business, and worse for your hair. Wherever I am, there's something not there.
Hard to catch, easy to hold. Can't be seen, unless it's cold
What is lengthened by being cut at both ends?
What lies in a tunnel of darkness. That can only attack when pulled back?
What runs around all day. Then lies under the bed. With its tongue hanging out?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?