Can I use present with should have pp

Question

I know I should have waited a little longer but I can't wait.

Is it possible to use present simple tense ("I know") with "should have" (modal verb)?

Answer 1

should have shows that you didn't do the action. Instead, you did something else. So after this, the past tense follows:

I know I should've waited a little longer but I couldn't wait.

know can also be substituted by knew, and the difference is clear.

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With a little more of context, this can also works:

I know I should've waited a little longer but I can't wait till tomorrow!