Why do some geniuses act silly and stupid when they know they aren't?

Few geniuses are gifted in all areas; most are specialists.

If it takes an average minimum of 5-10 hours of purposeful daily practice for a minimum of ten years to become the world's best at something, there's a high likelihood that basic life skills may be underdeveloped.

God your questions are getting hard to answer...I'm going to go with a split personality or maybe they  just need at times to act their age....:( 

Because their anal warts are acting up.

Everybody needs to blow off steam occasionally. "A little nonsense is cherished by the wisest of men" (Kipling).

It's more fun to act silly every now and again. Even geniuses like to let loose and have a little fun.

they nnight not want people to know how snnart they are

Guh HyuuUUUK.  DuhhhhhHHH  I don't NO Boss!