Usage of a little and little [duplicate]

"A little" - small quantity, but enough for its purpose. "Little" - small quantity, but not enough for its purpose.

I have a little free time, so I can help you.

I have little free time, so I can't help you.

I drink a little alcohol every now and then (just enough to relax).

I drink little alcohol (hardly ever and barely enough to have any effect on me).

It's the same with "few/a few" for countable nouns:

I have a few friends, not many, but that's enough for me.

I have few friends. I wish I had more of them.