Instant gratification is wanting pleasure or fulfillment right now. An example would be wanting your job payment; you wouldn't want to wait longer than you have to for it, would you?
Here's your monthly pay
No Instant Gratification
I am so sorry for the delay. Please be patient and I will give you a bonus when the time comes.
Sorry. You'll have to wait another three weeks...
What is Delayed Gratification?
Delayed gratification is the ability to resist a temptation of an immediate reward for a later reward (usually it's a better reward). An example would be saving your money. You COULD buy one really cool new pair of shoes, OR you could save up longer and buy the shoes as well as a new shirt.
I could buy these cool shoes... but if I waited another week I'll also have enough money for that shirt to go with my shoes!
Benefit of Delayed Gratification
Alright! Now I can buy both the shoes and the shirt after waiting a week! Everyone at school is gonna love my new outfit!