But – negates any words that are stated before it
If – presupposes that you may not
Would have – past tense that draws attention to things that didn’t actually happen.
Should have – past tense that draws attention to things that didn’t actually happen (implies guilt)
Could have – past tense that draws attention to things that didn’t actually happen, but the person tries to take credit as if it did happen
Try – presupposes failure.
Might – It does nothing definite. It leaves options for your listener
Can’t / Don’t – These words force the listener to focus on exactly the opposite of what you want. This mistake parents and coaches make without knowing the damage of this linguistic error.