Being a sailor during the age of sail was a difficult job, but so was being a farmer, or a tailor, or a rope-maker, or a carpenter, or a whole range of pre-modern jobs. We know that sailors were fiercely proud of their skills, to the extent that British ships heading home from Malta in the early 19th century would have the captains of each mast dance a hornpipe on the top of his mast whilst leaving Valetta, to the celebration of the ship's crew.

Food aboard ships would certainly be monotonous, but rations for sailors were guaranteed at 16 oz to the pound, and included perquisites of tobacco and alcohol; the sailor's daily meals packed in about 5,000 calories, which is more than many contemporaneous day laborers could hope for in several days.

Discipline on board ships could be harsh, but except in some unusual cases did not result in violence among the men or directed towards the officers, aside from the violence inherent in being engaged upon a weapon of war.

Sailors were generally literate, compared with the general populace, and well educated in language (useful for ... conversations ... with foreigners they encountered in their travels) and in mathematics, necessary for navigation; they were by all accounts less religious than the general population, and drank more (the basic issue of alcohol in the RN was based on a gallon of beer per day).

Mortality per annum from disease has been estimated at 4.5 percent, and by shipwreck less than 1 percent, while battle deaths are statistical noise -- very unlikely for most seamen. Wages in the merchant service were generally higher on average, but merchantmen were not subject to sudden and unexpected showers of gold from prize-money. So on balance, the life of a mariner was not notably terrible on its own; it's not particularly surprising that many men (and a few women) chose this of their own will.