The word "unrealistic" means something that is not likely or practical to happen in real life. It describes ideas, expectations, or plans that are not based on reality or are difficult to achieve. Full definition
This includes our relationships and I think we have an epidemic of unhappy people who are unhappy because of unrealistic expectations of how life should be. (omgchronicles.vickilarson.com)
This is science fiction with giant fighting robots, and it was completely unrealistic in more moments than not. (awardscircuit.com)
The worst case scenario is that you ignore rebalancing completely, so don't set unrealistic goals that you can't commit to. (monevator.com)