I find that I never get drunk on a cruise partly because the prices are so high so I never have more than 2 at a time and partly because my belly is always full! I usually drink cans of fosters beer because that is the cheapest per ounce for a semi-quality beer. I'm probably the cheapest person on this forum, but I've been waiting 2 years for this cruise and I'm going to get what I want. I am going to have red wine with all my dinners and if I want a second, I'm going to do it! Now I'm a little afraid of my what my wife will order, those mixed drinks are hella expensive!
I look at it this way, I try to buy the cruise at a time when it is cheap when I consider travel vessel, lodging, and meals, so the drinks and a few souveniers are how they make any money from me.
BTW, I'm never cheap on tipping. Be cheap on yourself all you want, but not on others.