in winter, wooden floor feels cold to the barefoot but the rugs and carpets don not feel cold although the floor and carpet are at the same temperature?
The conductivity is so low that you do not notice the effect. Both have a lot of air (bad conductor) and wool (another bad conductor, especially as it contains more air inside).
Assume that the temperature of the inside of your foot is always the same and the temperature 'below the floorboards' is also the same. There will be a thermal gradient from your body tissue, across your skin, through any insulation and the floor. If the intermediate layer has low conductivity, the surface of your skin will have a higher temperature (It's not just an illusion) because there will be a greater temperature drop across the insulation layer and the overall rate of heat flow will be lower.
There is a direct analogue here with an electrical potential divider, consisting of a chain of resistors, where the PD is shared across the resistors. Inserting a high value of resistor in series with a resistor will reduce the total current, which will reduce the PD across the original resistor.