My best tip for enjoying Cuba is your own actions.
Be polite and understanding not loud and demanding.
I will give two examples I am sure everyone has more to add.
If you do not like your room you may go to front desk and ask to be moved to a different room. Ask nicely you may have to wait tell the next day so what big deal live with it. Or you could scream bloody murder and say the room is not fit for a dog. Bet ya I get moved quicker to the best room they have available. If by chance the bar runs out of fresh mint for your drink no problem tell the bartender don't worry it's all good. Or you could scream bloody murder and say you paid good money to stay in this dump.
The bartender may call me over the next day and say senior I brought some fresh mint from my house for you. Chances are no fresh mint for you.
Try to put yourself in the shoes of the person who quite likely is trying to help you. Many times what you are asking for simply is not available.Relax and enjoy go with the flow or the person most likely to ruin your holiday will be you.