General:
* Simple
* Effortless
* Uncomplicated
* Straightforward
* Painless
* Smooth
* Undemanding
For tasks:
* Manageable
* Achievable
* Doable
* Trivial
* Child's play
For understanding:
* Clear
* Understandable
* Accessible
* Straightforward
* Lucid
For feelings:
* Relaxed
* Comfortable
* At ease
* Unburdened
For situations:
* Relaxed
* Comfortable
* Pleasant
* Breezy
* Laid-back
The best synonym for "easy" depends on the specific situation and what you want to emphasize.