"Hi" (with a smile) is a perfectly good greeting when passing an acquaintance on the street or in a hallway.

Don't you just love the folks who ask "this" with a pace that doesn't slow down for an answer?

I CERTAINLY don't want to be a "sad sack" OR bragger! With family/friends, I TRY to be as honest as possible (with a positive slant). You want to protect the people who love you, right?

How often are you absolutely honest when someone asks you,

"How's it going?"

Depends who's asking. But often I am honest.

Hi BF!

Here in Texas it's how I make new friends

^^^^Perfect! Too Both!

Howdy!

Hi Beach

Never.
It's not possible to be "absolutely" honest.

Otherwise, I'm about as honest as when someone asks:
"Is there anything else I can do for you?"
"What else can I do for you?"
"Did you find everything you need?"
"Would you like anything else?"
"Can I do anything else for you?"
"Do you have spare change?"
"Could you help me out with some gas?"
"What's up?"
"Would you like (x) for a dollar more?"

And many many other questions that are relevant to context and consequences.

Heya Wicked Cool (ole mingler) Right Coaster! Good to see you Sweets! ("Genuinely"....So good to see an Old Schooler!!!)

It has definitely been a while! Good to see a familiar face.

To answer the question in your OP, it depends on who is asking.

How is it not possible to be absolutely honest?

I am honest with this always..
Doesn't matter who..

If asked most of the time I answer with ..

A smile, short chuckle, and going... if it is not.

If it is "going good"
I answer
smile, chuckle and great... wonderful etc...

I am so freaking literal (****-retentive) that I auto-respond
immediately with exactly how I am..then the brain catches up.

Literal people have a hard time prevaricating so I speak and
reply exactly as I do on here :-)