your first/first two jobs quite impt cos it gives you the exposure and tune your mindset.

gd if you go into a 'competitive or performance based' culture in private sector. you start off working hard, learn as much as possible, develop your skills/abilities/competencies etc. it will give you a good foundation as you move up in the future. of cos, you can be subjected to retrenchment if market or coy not doing well.

public sector normally has a more 'shielded' environment and qualifications play a very big part in your progress. that is not to say that its easy in public sector. its not an iron rice bowl anymore but then they still cannot anyhow retrench you. if you not performing, at most you just stuck there and receive your measly pay every mth. but yup, it can be hard if you move to private cos you are not used to the culture in private sector.