There’s a big difference between the result you really want and the result you know you’re going to get. Shooting for a better outcome than you want to end up with is the best way to hedge against the delta. Once you throw out the high end result it’s then important to manage the process to get to the final point (sort of goes hand in hand with the 70% complete rule for delivery).
It can occasionally be demoralizing for a team to have a stated goal that they know is unattainable. If you shoot too high it’s possible you don’t even get the outcome that you want. Management of actual delivery expectations is as important as setting a high bar. Your team is going to be the ones that are making you look good – helping them understand the difference between stated and desired is important. You don’t want to lower the bar for them and not have them reach for more than they think they can achieve but you also can’t let them think they’ll never be successful.
Life is often about balance. Yin and yang. Finding that is hard but important.