Why is a new brush shape selected when I click a tool?

Question

This has bothered me for years. Its a problem that has plagued me and all my friends/family since Photoshop 5.5, when I was 11. Sometimes, I hear this problem breathing and salivating in my closet at night. It ate my brother, too, which was a horribly mean thing to do.
But the craziest part is that it only happens once in a while. And when I finally make an action so I can hotkey back to reality on-the-fly, it eventually just stops occurring. No changes in setting or anything.
Here's what happens:
1. I use a brush tool. (Paintbrush, clone stamp, pencil, etc.)
2. I use something else.
3. I select that tool I was using.
4. The brush has changed to some random stupid useless setting that noone in their right mind would ever use.
That's it. I'll be clicking along happily, cloning over wrinkles with a soft round 20px brush. Then I'll go zoom into a spot. Then I click the clone tool, and WHAT DO YA' KNOW! It's decided that I need a 120 px textured semi-opaque sponge brush with 50 pixel jitter. I swear it laughs at me when this happens. Its like Photoshop is rickrolling me.
So anyway, that's the backstory. Here's my question:
Should I go on living?

Answer 1

Well the four steps outlined above are really the entire issue. The rest is fluff. I have a congenital sarcasm condition.
1. I use a brush tool. (Paintbrush, clone stamp, pencil, etc.)
2. I use something else.
3. I select that tool I was using.
4. The brush has changed to some random stupid useless setting that noone in their right mind would ever use.
In terms of literal action:
B...click-drag...J...click-drag...S...alt-click...click-drag...B...::tear hair out, curse loudly, bellow such that atlas himself cowers, cry a little::
Every time the issue crops up (unexpectedly and intermittently - while its been happening since the dawn of time, when Photoshop and Image-Ready were the only two programs on Noah's ark, its only come about once every four months or so) it happens to a different brush tool, and a different brush preset. However, once its decided which frankenbrush to use, it sticks to it with zealous, patriotic loyalty. I have noticed, though, that it tends towards those brushes that are only useful with Wacom equipment. (Drivers for which aren't installed on my machine.)
The only way I've found to reliably produce the issue is to turn on my microphone and loudly proclaim, "what could possibly go wrong?" (No, I can't reproduce it at will. Sorry.)