For uncountable nouns, 'a little' means 'some', while 'little' means 'not much'.
For countable nouns, 'a few' means 'some', while 'few' means 'not many'.
Whether or not you see these ideas as positive or negative depends on whether they are good or bad things. For example:
'I have a few very close friends' is a good thing. You are happy that you have some very close friends. But 'I have few close friends' is a bad thing. You unhappy that you don't have many close friends.
Conversely, 'I had a few problems' is negative, whereas 'I had few problems' is positive.