People always have expectations of you, most especially time expectations, quality expectations, and they expect you to deliver.
When you work with people, be careful how you tell them you will do something or when you will do something. Even if you don't use the exact word "I promise", they will hear it.
You are a vendor contracted to supply drinks for a party of 4pm. Tell the client you will supply by 4:10pm - Under promise, but do all your best to be there by 3:30pm - Over Deliver.
Tailors, food vendors, delivery agents are mostly likely the culprits who fall into this trap, you know many circumstances can after your possibility of making a delivery on time yet you promise to deliver a dress way earlier than you know you can. You tell the customer you will finish it in 2 days. Why? Then you begin to rush and also endure unnecessary backlash from unsatisfied clients.
At work, if you are to resume by 9am, be there by 8:30am. And you are to close by 5pm, don't leave until 5:10pm.
The advantage is that, when you consistently under promise and over deliver, you set yourself in a state of equilibrium, no one can fault you and no one can force you to do more than you can. You effectively get rid of discombobulation,
If and when you cannot meet up with the expectations of people one day maybe due to unforseen or uncontrollable circumstances, they will not even be able to complain because you have always over delivered in the past.
Give yourself peace of mind.
No matter what, it's good to always be at ones best in everything at it accords one full respect if people sticks to the words they say.