I wasn't able to find the whole article, but I found excerpts.
He seems to be making the point that low-responsibility jobs are an attractive path to happiness. By not investing personal commitment to the job, there is no humiliation in failure, and there is no disappointment in lack of advancement. He contrasts his father's sadness at losing a job to his own indifference as losing his.
I feel obliged to quote Theodore Roosevelt for necessary contrast:
"Far better is it to dare mighty things, to win glorious triumphs, even though checkered by failure... than to rank with those poor spirits who neither enjoy nor suffer much, because they live in a gray twilight that knows not victory nor defeat."