As a general rule I would say no, but it really does depend on the secret & the circumstances. As it's a possibility I can't dismiss absolutely I have to say yes it can be ok to keep secrets.
I trust that if my wife is keeping secrets it's for the right reasons, even if I disagree with her once I've learnt the secret.

Never been 'captured' sooooooo Yeah I think it's bad.

I want to be clear that surprises and secrets are different things in my books. Having said that, honesty is the only absolute rule in my personal relationships. It's a matter of respect. Don't demean me with dishonestly.

You need to keep secrets otherwise you'll be a boring open book. Always need to keep surprising them.

As long as the secret doesn't negatively affect your partner or involve cheating I suppose it might be ok.

If you are lying about the big stuff then you should fix the situation. Stop doing things you need to cover up, and/or, restructure your relationship so you can be honest, and/or, end your relationship.

Each of these can be anywhere from easy to excruciatingly difficult.

To me, being an agnostic/atheist leads me towards radical honesty. I only have one life so I want to experience it authentically and not miss anything it has to tell me.

Is that a healthy marriage?

I don't do polls... from strangers.

Sometimes you just gotta

Not if you want to stay married. Secrecy is just another form of lying & I hate liars. My husband's secrets & lies have destroyed our marriage to where there is no hope of repair.

No secrets just breed mistrust and eventually unhappiness. In general secrets are bad for relationships.

Sure