Medicine: Why are we sceptical about the AstraZeneca vaccine

Why are we sceptical about vaccines?
Why are we specifically sceptical about the vaccine of AstraZeneca?
Governments need to remember that not only their citizens but also, they have difficulty seeing the bigger picture. We have our PSYCHOLOGY standing in our way. But the coronavirus and the COVID-19 pandemic has shown that all people and all countries are interconnected. We can no longer pretend otherwise.