Two words people get mixed up are "hope" and "expectation". When your hopes don't come true, you may think something on the line of, "Shucks, that didn't happen", but you get over it. If you are expecting something and it turns out not to come true, you get disappointed. Results of disappointment may include, but are not limited to, lack of appetite, poor mood, laziness and lack of motivation, lack of creativity, anxiety, displeasure, or life seeming to just generally suck. Having absolutely no expectations is ideal, but I have a hard time not expecting anything in a given situation. Setting your expectations too low is good too, but if you really believe your expectations they still may inhibit you from doing things as effectively as possible, with them high or low. My solution is to just take your expectations with a grain of sand. For example, if you are a business owner and you expect your employees to all be on time, those expectations may or may not come true. If they don't, then don't get bent about it. Things happen. Maybe that late employee had to take care of their children, or got stuck in traffic during a five-car-wreck, or a million other things. (My personal opinion is to not even act bent with the employee, you want them to like you, not fear you, however that is for another time. Go thru life care-free but caring.) Anyway, if all your employees are on time, then be thankful for that. Tell your employees nice job for being on time. Things will get on your nerves about a thousand times the amount if you base the totality of existence on your expectations.
I know it's a bit of an abrupt ending, but that's all. I hope (but don't necessarily expect) you to have a nice day!