gtyg
meaning "good that your good" like to say u appreciate that they're ok after asking them how they are.
Me: How are you?
You: Good hby?
Me: Im g, gtyg.
You: Good hby?
Me: Im g, gtyg.
gtyg
meaning "good that you are good" appreciating someone's feelings are you ask them how they are.
Me: how r u
You: Good hby?
Me: im g gtyg
You: Good hby?
Me: im g gtyg