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 he has the enthusiasm to gamble because he has felt the pleasure of winning once or twice, then he is very enthusiastic about gambling even though he often loses there. and what you say is true or maybe he feels comfortable with all the gambling games he plays so he becomes addicted and then he forgets that gambling is very high risk and what he thinks is fun and enjoyable.