Both Nottingham Forest and Aston Villa deserved what they got, because they gave up on the UCL qualification race on the last minutes when they were almost there. Forest couldn't win their last match when they know that was the only chance that they have to win Chelsea and qualify. Villa's goalkeeper messed everything up for them due to the red card he got and gave the match to United.
Aston Villa and Nottingham Forest can try again with a much better performance next season because they also finished this season in a fairly good position. So they don't need to be disappointed with the results they got because this season there were many tough opponents to beat until the end of the season. And I also praise the performance of both teams this season because previously both teams also often troubled the top teams in the middle of this season.