One of the most common pieces of advice is to not get too emotionally invested in one company or job. There are many reasons, often out of your control, that determine whether or not you may receive an offer. Even if you have some roles you are especially excited about, it's important to realize that on some level job hunting is always a numbers game. Having multiple offers in hand allows for leverage to boost compensation and optimize for the best fit. This is all extremely reasonable advice that I regularly give. That said, I have confession to make:
I have never had more than a single outstanding offer in hand.
Not for lack of trying mind you, I have cast a wide net many times, especially in college. I have just failed to get more than one at a time which has led to my decisions being fairly straightforward.
This is fine! I would even go so far as to say this is expected if you keep pushing the boundaries of what you thought possible. You don't need to have multiple offers to make a decision and it would be counterproductive to let good open offers expire solely to get more options or leverage.
In a famed study of amnesiac patients, it was found that participants given a Monet print with the option to come back later and swap out the print not only liked the print they chose less than those who just had to stick with one, but grew to like all of the prints less! The moral is to avoid pursuing lots of offers as the end goal, the moral is to interview widely with the intention of finding at least one offer that is right for you. As an upward stumbler, I assure you that all you need is one.