When a person steps from a shower on a cold morning, why does the tile floor seem so much more colder than the air.

Because our body heat is really hot compared to the cold tile floor. The tile floor can be as cold as the air you just can't notice because we can actually feel the temperature by touching the tile floor

Their skin is accustomed to the warmth of the water in the shower and so by comparison the tile feels cold. It's like if you went from outside on a cold winter day to inside, you would instantly feel warmer.