From Roman Jakobson's memoir My Futurist Years:
In 1918 or 1919 Mayakovsky and I were walking along the street in Moscow, when suddenly he asked me: "Listen, canI ask you something that may strike you as strange?" I said: "Ask away."--"You're walking along the street alone and suddenly you notice that you're thinking of something incredibly stupid, silly, and meaninglyess, and that you're thinking about it in a concentrated way. Does that ever happen to you.?"--Oh yes, it happens all the time."--"Thank God, I thought it happened only to me." This is very characteristic for Mayakovsky's psyche.