In how many ways can you choose 2 side dishes out of 8

The first choice can be any one of the 8 side dishes.
               For each of these . . .
The 2nd choice can be any one of the remaining 7.

     Total number of ways to pick 2 out of 8 = (8 x 7) = 56 ways .

BUT ...

That doesn't mean you can get 56 different sets of 2 side dishes.

For each different pair, there are 2 ways to choose them . . .
(first A then B), and (first B then A).  Either way, you wind up with (A and B).

So yes, there are 56 different 'WAYS' to choose 2 out of 8.
But there are only 28 different possible results, and 2 'ways'
to get each result.