Expecting to succeed seems a sine qua non of any venture. However, it is evident that many ventures, if not most, do fail. So one needs to be ready to not succeed as well.
But what is interesting is that both the highs and lows, when looked at from the outside, look to be caused by the expectations themselves.
If one starts out with a position of equanimity, it appears that, no matter the result, one comes out ahead with having learned something from the experience.
As Krishna advises Arjuna in the Bhagavad Gita (Chapter 2, Verse 47) a position of detachment to the results is often the best approach.
karmaṇy-evādhikāras te mā phaleṣhu kadāchana
mā karma-phala-hetur bhūr mā te saṅgo ’stvakarmaṇi
A rough translation of this would be:
You have a right to perform your prescribed duties, but you are not at any time entitled to the fruits of your actions.
Never consider yourself to be the cause of the results of your activities, nor be attached to inaction.
The second line of the verse is a reminder that one is not in control of the results of one’s actions. At the same time, a position of detachment should not lull one into not taking action.