Having attachments and expectations is natural to human kind.You cannot deny yourself saying it is bad or not ok to have attachments and expectations. For example, you can tell to yourself that you will have zero expectations in life but the reality is when it is time for dinner your stomach expects some food, when you are thirsty your body expects you to replenish it with water. Expectations are part of life. Denying it is going against nature. But what we need to understand is that our attachment and expectations should not lead to greed, lust and possessiveness.They are the root of all evil.