And by this, I mean whatever comes to mind that you might be hiding.
The thing is, humans don't really need honesty. We need reliability, somewhat. We need predictability, often. But, honesty is actually quite optional. If you tell somebody you hate them, that may be honest, but not useful. Maybe hate is not really honest at all times. It could be an emotional outburst that, like a knife, can slice open feelings and leave the unaware person bleeding hard-won self-confidence. Sure, you were honest. You got your slice in. But, you're still in the relationship, so you now have scar tissue to deal with.
Honesty may well be more about being vulnerable and trying to get feedback and perspective. In that case, it's likely most important that you're first being honest with yourself. Will you be able to say, objectively, what is actually happening? Will the results be part of the truth that gets communicated or will you try to sugarcoat the details and make them seem more acceptable than they otherwise might be?
Honest with others is important, but honesty with self is vital. But, what if we have a blindspot and cannot be objective about our own reality? That's when it's really important to not only be honest, but also humble. We have to ask for ideas and thoughts without being resistant. We have to ask with sincere curiosity about what could be going on and how the real world is perceiving us.
On a scale of 1-10, I'd say I'm being about 6.5 honest. Though that sentence doesn't read well, I have some ideas. A 10 would be 100 percent honest and a 5 would be half lying most of the time. A 6.5 means you have some positive intent but don't necessarily trust the recipients of your truth to be able to help you in any meaningful way, so you're not going to give them all the juicy details. In summary: Honest with positive intent. Reserved enough to keep everybody feeling good.