They believe that a successful career offers people with self-fulfillment and confidence.
... good beginning :)
For them, the relaxation and joy provided by social life valuesvalue more
... relaxation and joy = two things and hence plural
I think different people will give varied understanding of what has more effect on happiness.
I think different people have different perceptions about what make them happy.Very impressive introduction! :)
My father is a businessman and he values work above all...
This is a very good example. However, you better first state your reason and then back it up with this example. The reason here is that for some people are very passionate about their work and they value the pleasure that is derived from work above everything else.
Also, be careful of lengthening your paragraphs, because you've really got to fight with time at the exam :)
You write well!