Question

The sun is an average sized star. most of the other stars in the galaxy are approximately the same size as the sun. why do the other stars in the galaxy appear so small in the night sky?

Answer 1

They are very far away from us. Sun is closer to us
If u see a person who is far from u it will of course look small..
But when you see a person close to you he will not look smaller right?
so, these two cases are same.

Answer 2

The sun is closer to us compared to other stars.

The other stars are further away from the sun. Hence, they appear quite small and the sun appears quite large.