Maintain your character's power!
This is a simple acting technique to sustain emotional tension in any performance, from stage and film to public speaking.
I borrowed this tip from actress Emma Thompson who, in turn, was given this advice early in her career.
CHAPTERS:
00:00 Why "never cry, never sigh"?
00:23 Emma Thompson
00:49 The problem
02:05 The trick
02:59 Playing anger
03:23 "Transforming" a cry or sigh
03:47 Exceptions
04:03 Liam Neeson