1 is an unlikely value for a "couple" just because I am more likely to KNOW when a small value is exactly 1. This is not because of the meaning of "a couple", but rather because there are more processes which can apply to reduce my uncertainty at that quantity.

For me "a few" is also an approximate number. I can't believe in a hard dividing line between "few" and "couple" because a sharp lower bound is antithetical to the whole concept for me!

"Several" is also an approximate number, but like 42itous posted, it has a connotation of "distinctness" between the range of elements. That connotation is totally absent for me in the "a few", even if they might both easily apply to the same *number* of items.