My oldest DD (now 25) has this issue. When she was a child I used to pull the seam part out about 2 inches and fold it over, it helped but didn't solved it (I was broke when raising her so no fancy seamless socks for her, do they even make those?). Now as an adult she "never" wears socks that I know of and is always in flip flops, thank goodness we live in CA.