If we expect too much and it doesn't happen, then we'll be disappointed.
But lowering your expectations and playing small isn't the answer either.
Even though lowering your expectations and meeting them might make you happy in the short term and help you to avoid disappointment, it'll crush you in the long term.
Because playing too small will lead to disappointment some time in the future.
You might not care about the future right not.
But your 80 year old self will probably care a great deal about it...