You're right though there are some person who feel excited while gambling, regardless to there loses yet they still feel excited,reason been that they know gambling itself is just part of fun. they are just playing for fun,and also for intertainment, they don't expect wining except when luck is on there side that is when they can win.but there are some person who bet more often hoping for luck to always be on there side everytime they gamble, and this set of people doesn't feel excited when gambling,because they intend to be wining whenever they gamble.
Maybe you forgot to add that those who gamble for fun and are happy whether losing or not are those who gamble with the amount of money that they can afford to lose. They don't gamble with all their worth and expecting to win by all means rather they believe in the luck aspect of gambling and as such act accordingly and not to bet hugely to win jackpot. If you gamble with little money that you can afford to lose then your mind will still be at peace like you never lost anything but in the case where you have to empty your bankroll to gamble, you will feel depressed for the moment that you lost. So the amount staked is also contributory to how you feel when you lose.