I've not been attacked by deer yet, but it's a distinct possibility. So far it's only a few badgers (out in kansas) that decided they wanted to be persistently aggressive, though we came to an understanding with some persuasion from a shovel.
Deer are absolutely capable of attack though. While they normally try to just fuck off, there are a few situations where otherwise can happen:
1. For unprovoked attacks, Male deer can be territorial, especially in a rut where they basically get seasonal roid rage and decide to square up even with the creepy things that walk around on two legs. Getting stabbed with antlers and pounded by hooves is dangerous.
2. If deer (male or female) become used to humans because they are being fed, then they lose their timidness and can get mean if they think it'll get them what they want, though they are unlikely to have the goal of killing.
3. They can also attack if their young are nearby. I come across baby deer roughly once a year, and while usually the mom is somewhere else for most of the day, that may not always be the case. I've been in hazelnut orchards, only to realize I almost just stepped on a fawn laying at a base of a tree. Pretty sure this raises both of our heart rates for a while.
4. Deer can also sometimes attack if they feel trapped and panic, generally from entering a neighborhood and having curious humans start coming around.
5. If you hunt deer, sometimes they'll decide to fight back or not be as dead as you think. Fair enough, TBH.
6. They can also become rabid. This is a good time to remind everyone that all animal attacks should immediately be followed up with a medical examination, no matter how minor any injury. You are vastly more likely to survive trying to commit suicide with a gun, than untreated rabies. Tuberculosis and all the other diseases and parasites they carry are also a consideration.
Horses and Cows will also wreck serious shit if they become inclined. Deer, horses and cows each cause something like a few dozen deaths (not to be confused with attacks, which is far greater) each year, similar to dogs. While bears cause something closer to just 1 death per year when averaged out, and mountain lions and rattle snakes are something like 0.25 deaths per year averaged out. All these numbers are very rough, as this is from foggy memory from past investigation, rather than a nice and neat source I have on hand. As an aside, most rattlesnake deaths are from a drunk deciding to mess with a snake, getting bit, and decide they're fine and go to sleep instead of the hospital. Big rattlesnakes aren't really a danger, just take a hint and leave them alone, they are fat and lazy and really don't need your shit.
Comparatively, things like driving my truck around, or even my ATV is a far larger source of danger, with ATV deaths being in the several hundreds per year I believe. But most of those are not likely from people puttering slowly around like me for crop inspection work.
Only slightly related, but prior to Oregon's partial drug legalization a short while ago, there was a non-zero danger of running into someone in the mountains looking after their million dollar weed plots and no interest in witnesses. There were areas that law enforcement would straight up refuse to go because of Reefer Rambos crawling about.