How is controlling the rate of a chemical reaction useful to a chemical engineer, physician and chef?

Controlling the rate of chemical reactions is crucial to a chef because that is what gives food its flavor. Bread that rises too fast or slow (yeast cells converting glucose into carbon dioxide) will taste awful compared to correctly risen bread. Flambé undergoes a very fast, but brief, chemical reaction when the alcohol in which it is smothered is ignited, caramelizing the creme on top. A slow reaction would melt it all, while an even faster reaction could cause the dish to explode.