You might find that to try and deal with your low self-esteem you behave in ways that are damaging to you and those around you. You might find that you try to 'escape' from life and engage in risky behaviour like taking drugs, unsafe sex or drinking too much. You might also develop an aggressive or violent personality to try to hide your vulnerabilities and protect yourself from further damage.
No-one is happy all the time, and having high self-esteem does not mean you will always feel confident about work or have successful relationships. However, good emotional health and positive self-esteem are strong predictors of happiness. If your core belief about yourself is mainly positive you may still associate with some of these behaviours, but your ability to cope with them will be much better.