A Few Too Few

Here is my take:

"Few" means small number.
As in: "there were very few people in the theater."
"A few" means 2 or 3.
As in: "there were only a few people in the theater."

I agree with the above. "few" is used to describe how many people are there. "A few" is used as sort of a noun. But they basically mean the same thing. Many times in English, phrases are shortened. So "a few" probably was originally said as "a very few".

"Few" is the opposite of "many"; it means the number is smaller than expected:
"Many people are invited, but few came."

"A few" is the opposite of "none at all"; it means "a small number of." So it sounds weird to say:
"Many people are invited, but a few came."

This is a good one! I think that you might think of it this way: few and 'a few' are the same thing, but use 'a few' if it is somehow qualified, e.g., '...but ONLY a few came.' vs. '...but few came.'. As a final note, if it were only 2 people, then most would say '...only a couple of people...', although 'few' is still correct.

Why focus on people? Maybe inanimate objects might offer some fresh perspective.

"A few tables were placed in the banquet hall, but few of the guests dared sit at them."

I would tend to say that "a few" refers to "a small number of"... while "few" means "less than expected".

Don't ask people where I'm from. Around here folks use the colloquialism "a couple few" when referring to an indefinite number of items as few as two and as many as...as...a lot, I guess. Sure, it sounds succinct, but couple it with the lazy pseudo-southern PA drawl and yew got yerself quite a phrase, boy howdy.

errrr how about if i say " there are few too applicants applied for this course, please select another course" what would be the meaning for "few too" here

Tanwir, I think you got that a little garbled. No one would say "there are few too applicants..." I think you meant "there are too few applicants..."
"Too few" means "not enough".
compare "many" = a lot, "few" = a small number.
Then compare "too many" = an unacceptably large number,
"too few" = an unacceptably small number.

Owl, The colloquialism, "a couple of" doesn't necessarily mean two. It can also mean "a small indeterminate number; two or more", just like "a few". I'm afraid if you really want to specify "two", you just have to say "two".