Enough expresses sufficiency; it shows there is as much as needed and there isn’t any more need:
- There are enough shoes.
- The house is big enough for our family.
Enough suggests a positive feeling about the situation.
- Not enough expresses insufficiency; it shows there is less than necessary or desired.
- There is not enough flour to bake this cake. (I want more flour.)
- The bathroom is not big enough (I want a bigger bathroom.)
Not enough suggests a negative feeling about the situation.
- Too expresses excess (more than needed) or insufficiency (less than needed) depending on the word that follows.
In both situations too suggests a negative feeling about the situation:
- The price is too high. (EXCESS: The price is higher than I want to pay.)
- The bed is too small. (INSUFFICIENCY: (It is less than I want, I want something bigger.)
- This tea is too cold.
- He talks too quickly.
- He is too young to drive.