The best course of action depends on when they happen (i.e. in response to which action).
Good places to start:
- Crash, exit or high CPU when right-clicking certain files
- Crash, exit or high CPU when viewing certain directories
- Automatic crash logs (for bug reports) (may not apply if it's freezing but not crashing)
- Manually generating process snapshots (can be used if it's freezing and not crashing)