- "I should have done X" (regret because X wasn't followed)
there are probably as many:
- "I should not have done X" (regret because X was followed and made things shit)
Even the "should not have worked as hard" would be most likely balanced with others saying: "should not have been as slack or loose at work, and did something important, made some legacy"
In the end, nothing really matters, and the perspective at the deathbed might have hindsight in its favor, but it's equally blind to the consequences of alternatives that weren't followed.