Having expectations and pursuing gratification can do wonders for your productivity. The former gives you aims while the latter gives you rewards. But it can become counterproductive if not formed well or delayed enough.
In the case of forming expectations, you don’t have to limit yourself to what is most “realistic” and therefore settle, but it may help you to find the spot that works for you between being firm and being flexible with them. E.g. What is within your domain and what isn’t? You can push yourself to do your most and/or your best, and expect that of yourself, but it doesn’t quite translate the same way when expecting that of people or life itself - there’s less you know to account for and less that you govern over. So, to some degree, you must leave matters to chance and be adaptable enough when whatever comes. Yet, it tends to be the case that odds will be in your favor if you strive for excellence - just as long as you don’t insist in fitting into places that you’ve outgrown.
When it comes to delaying gratification, it can be tough but it is doable. But like with forming expectations, there’s a sweet spot that you must find for yourself. One between being able to go without it and being kind to yourself regardless. Being a joyless machine can only get you so far. And primarily chasing after joy will turn your process into a roller coaster ride. That said, gratification may come with what you're doing, when the tasks at hand are inherently fulfilling and you are appreciative enough to derive fulfillment from them, or found outside or after the task, like listening to nice music while drinking a cup of your favorite tea or by getting feedback and collecting a payment. For example. What is gratifying is innumerable and often not obvious. It is also specific to each person, though underlying principles might be the same.
We are prone to frustration, when we’re too heavily reliant on expectations being met and gratification being granted. This frustration can be a sign that they are of extreme importance and should not be taken lightly. But it can also mean that they’re backfiring on you and should be revised.