General opposites:
* Difficult: This is a very broad opposite, implying someone is hard to deal with or work with.
* High-strung: This suggests someone is easily stressed, anxious, and perhaps prone to overreacting.
* Uptight: Similar to high-strung, it suggests someone is rigid, inflexible, and possibly controlling.
* Demanding: This refers to someone who has high expectations of themselves and others, and can be difficult to please.
* Rigid: This implies someone is inflexible, stubborn, and set in their ways.
More specific opposites:
* Controlling: This focuses on someone who likes to be in charge and dictates how things should be done.
* Picky: This highlights someone who is very particular and hard to please.
* Stressed: This emphasizes someone who is easily overwhelmed and anxious.
* Short-tempered: This points to someone who is easily angered and quick to lose their temper.
The best opposite for "easy-going" really depends on the specific context and the aspect you want to emphasize.