A realistic person will tell you how things are, and how your potential perspectives look. A pessimistic person will focus solely on the bad parts of the predicament. A supportive person will likely tell you how things are, but put much more emphasis on the positive side of things. A person who is not supportive will likely just be extremely negative with a lot of personal bias.
With that out of the way, I want to discuss a topic that is common in support groups. People in support groups are there to give advice, tips, etc. for all things that are related to whatever you’re in the support group for (emotional abuse, spousal abuse, drug addiction, chronic illness support, etc). Everyone comes to these groups (online and/or real life) with a different background. Some have a positive outlook, while others will drag on and on about the negative in their life (never considering the positive aspects in their life). Yes, it is so easy to get sucked up and succumb to the negativity going on in your life.
When asking for advice and tips, individuals will offer their own piece of the pie in this. However, for those who give realistic responses (state positive and negative factors, what could realistically possibly happen to them, etc) they are sometimes shunned in support communities. They are accused of spreading negativity, and not giving support to the individual.
This is bullshit.
Fantasy living, especially for any kind of illness is fine as a temporary escape. However, coddling individuals to death (especially in support groups), only further feeds a fantasy. If an individual gets to the point where they are 24/7 living in a fantasy realm (not believing what doctors tell them, ignoring serious physical and/or mental symptoms, denying suicidal thoughts when indeed being suicidal, etc), then this will only harm them.
Support groups by nature should be mostly positive. However, spoon feeding individuals and not being realistic with them (how doctors view them, how other patients may feel, etc.) can only lead to more damage being done in the long run.
Being realistic about something and telling someone the cold hard facts of the world, is not the same thing as being pessimistic.