What examples were provided of the rude awakening that could be expected? In Martin Luther Kings Jr. "I have a Dream" speech

Well the whole "rude awakening" affair is a bit vague but it refers to the whites who believe that African Americans are only blowing of a little steam and they could return their segregation ways. It was they who were in for a "rude awakening" as the African Americans won't give up until the segregation ends and everyone enjoys freedom and justice equally. Martin Luther King though states that the African Americans should only protest peacefully and not resort to violence.