Nobody can tell you anything without actual system information and a better explanation using proper technical terminology. What is "The brush tool will act crazy." even supposed to mean? Such vageu and generic statements are of no use to anyone.
I suppose you will find out what the "Brush Tool will act crazy" means when it no longer will switch from black to white on the foreground color, or you can't change the actual tip without it skipping down to the healing brush, the cloner, the mixer, or another tool. It does not do the same thing each time you click it. But hey......Mr. Technical Terminology Jock......speaking of generic statements that are of no use to anyone......you probably wrote the book on it. (No use to anyone....)