And they're like "your break is 15 minutes... don't be late or there will be trouble..." then are they sort of joking around, just another way to liven up the "i'm giving you your break" thing. Or... are they inconspicuously trying to assert dominance over you? Because I can't really tell.
And they're not a manager or department head or anything, just another associate, same as you.
If they're a relief checker, why does it matter to them how long you take a break? As soon as you get back, they're going to have to go into another lane anyway. Now if you worked in some place like the bakery department and there were only two of you there and you were both due a break, then I could see telling the person going on break not to dawdle.
Dont have to deal with this. I work in deli. I come in at 6am, take my break around noon, and then the other person takes their break at some point after that. The girl I usually work with prefers to take her break around 1 so it gives us plenty of time to play with. That way we dont have to be petty *******s and make ****ty "jokes" at each other, lol. Sorry you have to deal with that, OP. Thats garbage.
I'd say it depends on the situation. I know some people who have a way of turning a 15 minute break into a 30 minute+ break because they "lose track of time" or whatever excuse they have that night. If you're one of those types, then i can understand your coworker would be upset if say you're in a service department and you're leaving them all by themselves.
If they're just trying to make a joke, then depending on how they say it, it might be really jerk-y of them.
This is a bully dominance technique. Just ignore it. If it bothers you and they're not "joking" take it up with your FES. If your FES doesn't care then take it to the manager as a hostile situation. If they don't care then go above their head to the ethics board. Union does nothing to help you other than to record a hazardous situation. Customers and employees still do the same bull** that they still did on the day in question.