I agree with the last part of that, which is that which weapon is most likely to be handy, is most likely a stick, or an improvised knife, depending on your setting. But that doesn't mean they are easy to come by, which was the argument proton was making in the OP.
As for the rest, I'd agree that if you are aware of some sort of attack you might have a chance to grab something; that goes along with the idea of preparing something. Most of the time though, the better option is to avoid whatever the threat is, rather than grabbing a stick. For your example of a snake blocking the way while hiking, the better option would be to make a little loop and look for a better way across, if the snake looks to be a dangerous snake. Grabbing a stick and trying to move it or attack it only increases the chance of a bite. It's only in specific, contrived situations (You're hiking with someone, someone you're with just got injured and needs help ASAP, and the only way for you to get back is through a bridge/small trail surrounded by cliff/etc. that has a snake on it) where you can recognize an imminent threat, while at the same time not having the option of avoiding the said threat.
Granted, there are more likely situations, like photon's-a guy gets mugged, he gets out but his girlfriend/wife/friend is still there and needs help, but even then we're back to the situation of if you prepare for an eventuality, you get to decide the tool you prepared with.