Firstly i would like to thank you for pointing this out to people. As alot of parties expect us clerics to be able to handle everything, They put us at risk when say luring a demon from behind a dragon because we do not want them to die as it makes us feel bad when they do since we are cleric we choose to keep them alive. Some people just get mad at us clerics when they die when it really was difficult to keep them alive in particular situations that i have mentioned above. ._.
Your welcome, my hopes are that this Guide will lead to a better understanding of Clerics in parties such as the one you mentioned. It's a difficult job being a Cleric, but hopefully the Guide will assist in educating others... if any of your friends, party mates etc would benefit from the Guide, send them on over to check this out. Let them know as well that I am willing to answer any questions and/or comments that they may have.
It is hard to deal with people that get angry when a Cleric isn't a miracle worker, in these situations they need more healers in the party for sure... as I have stated in the Guide. Also the party's attackers usually seem to have enough time to chat while they play... if they have time for that (ok,i have to say it...) they have time to open up their inventory, take a large health pot and some candy to help take care of themselves as well. They too need to keep an eye on their own health, it's not your job to keep them alive, it's their job to keep themselves alive and you are there just to help out with that task.
When constantly healing and potting up with mana to keep your heals going, there is nothing more that you can do. Rest assured that you will find some people that will appreciate your help and your natural concern for their characters well being, and won't blame you for deaths etc. In my opinion, these appreciative people are the ones to keep in mind to party with the next go around... forget those that lose their temper with you, they are probably overly worked up by the excitement of the fight, they may later thank you for your efforts, but until that time to keep your sanity consider limiting your parties with them and concentrate on the ones that are a joy to party with.
Keep the people that are a joy to party with extra close as well as those that give you some extra mana pots for those parties they too are a treasure as we are taking mana pots almost constantly during these fights and we can only buy the small pots from NPC's and these parties tend to cost us a fortune in game gold to keep people alive.
As far as what you can do for yourself... you can learn (as I did) to say "no" to parties with certain players if you are not willing to deal with their unreasonable expectations or if they don't cooperate with working as a good party should (what I call a piece of well oiled machinery.) By your enabling yourself to saying the word "no" people will usually respect your decision, open their eyes to problems that certain players may cause you, etc... what's the worse that could happen? well they may not want you in their party as a result... but the best that can happen is respect for you and some self respect for you as well.
Good luck my fellow Cleric... my wish for you is to find the perfect people to join you in your adventures!