If you frequently run last-minute sales, don't be surprised if your customers stop buying things in advance. You're training them to wait.
If you announce things six or seven times, getting louder each time, don't be surprised if your customers ignore the first few announcements. You've trained them to expect you'll yell if it's important.
If you don't offer someone a raise until they find a new job and quit, don't be surprised if your employees start looking for new jobs.
The way you engage with your customers (students/bosses/peers) trains them on what to expect from interactions with you.
Drip, drip, drip.