Wheat broke out again on Friday in response to Russia extending its ban on wheat exports. Soybeans and corn both shot to key resistance levels (which held). Here is a wheat chart:
I traded the start of this wheat spike and got out much too early. When commodities have a major spike it is not necessarily in a straight line, and the recent spike could look like a blip on the chart if there is a major move. The possibility of such a move and the rewards it would offer are a strong argument for buying back in.