How to prefer fist over chainsaw iff you are berserk
When you have picked up a berserk box the fist is almost always a better weapon than the chainsaw. However, the chainsaw is preferred to the fist when pressing the "1" key to switch weapon. So to select the fist you'd have to first select the chainsaw, wait for the weapon to raise, then press "1" again, which would lower it and finally switch to the fist.
For this reason I would, for years, avoid one irritation by enduring another; I would carefully avoid picking up any chainsaws unless I knew there were no berserk boxes available on the map.*
This even carried over into Boom, which added a preferred weapon selection order. At least, that is how it seemed. Recently I have discovered otherwise.**
If you set the Boom weapon preference for the fist higher than that of the chainsaw, the weapon choosing code is intelligent enough to still prefer the chainsaw over the fist if you have not picked up a berserk box.
To me this was far from obvious and ran counter to intuition. Why would you knowingly set the priority of the weak fist over the chainsaw unless you had happened to read the code? I only discovered this when I went to try to implement a berserk > chainsaw > fist preference order, only to find it was already there...
* Unless the map had so much ammunition that I wouldn't care about either melee weapon, or unless the early part of the map was so devoid of ammunition that I knew I would need the chainsaw before I could get hold of a berserk box. There are always exceptions.
** Well, obviously. Why else would I be writing this post.