Think about driving on a clear day—then think about driving on wet roads, at night. Think about firearms practice on a warm summer afternoon, then think about the same practice on a cold winter night, with gloves on (or with semi-frozen fingers). Think about the training you've had, and ask yourself if you've been trained in job-related conditions.
The idea of job-related training goes well beyond this weather-based stuff. Do you train in low light? What about in residential areas, or in businesses? Do you go to the range in jeans and a t-shirt, or do you wear your uniform, including your body armor? When at the firing range, do you practice tactical movement, utilizing proper cover, or do you just stand there and shoot at a target? If you're training with your backup gun, do you draw and "re-holster" it the same way you would on the street, from the same carry location? What about your off-duty weapon?
We can keep going. During DT classes, do you get training with RedMan or other similar gear, or are your baton strikes "simulated"? Do you actually put handcuffs on your training partner (complete with double-locking), or do you just simulate the cuffing or the double-lock stage? Do you engage in full simulations, including verbal exchanges?
Have you taken an actual dynamic hit of OC while someone tries to take your training firearm, or did you take a "wipe" exposure (or none at all)? Have you taken a TASER "ride," or just watched it on video?
Here are some things I've seen happen in 22 years of training experience. You make your own list: