I feel like there are times when I would rather sit alone period, rather than trying to carry on conversations with people that I really don't want to talk with usually due to the subject matter of the conversation, ie politics, some sports, or especially work. These are the times that the privacy of the aft deck or in some others cases the patio just make the perfect places to chill and raise a toast to yourself.
There are a number of people who, for various reasons, don't drink alone. Some will open (almost) any rum in their collection for friends but not a single bottle for just themselves. An unshared bottle is a waste of money seems to be the feeling about it. This is the view of many, but there is nothing wrong with that for them either. Myself I'm not likely to open an unusual or hard to get bottle just for myself, but rather with a group so the sharing of the rum and the opinions on the rum itself can be bantered around is a much better way to enjoy these type of expressions.
If it has been a particularly slow day at the bar and my tip jar is empty, I find myself sitting of the boat mixing a cocktail from the bar on the boat saving some money. As a member of the service industry, I cannot go to a bar with out leaving a good tip for my bartender, so rather than disrespecting the person that has served me. The cocktail on the boat itself is a lot cheaper as well.
I find that depending on mood and other considerations, I may have a cocktail alone, but I really don't feel that there is a negativity that is attached to the cocktail if it is for the right reasons and it doesn't become a place to hide feeling sad and depressed. Rather it be a place of quiet joy and smiles while you toast to