From the comments in this thread, it seems that to understand how Forth implements a simple IF-THEN-ELSE control-flow, I have to understand the difference between non-immediate and immediate words. I also have to understand the difference between outer and inner interpreter. And I have to understand how Forth generates snippets of machine code (where does that get stored? I thought Forth only has 2 stacks, does it also have a general heap?). Then understand how the THEN token goes back and patches the placeholder address generated by the IF token. And understand the difference between the parsing phase and the interpreted phase of the Forth interpreter/compiler.

But you are saying that the Forth version is simpler than C version which will kinda look like this after it's compiled (Z80 assembly code, it's in my head right now):

    ld a, (variableN)
    cp 42
    ld hl, StringHey
    call z, Printf
    ...
 StringHey:
    .db "hey!", 0

It's fine, I can't force you in either. Maybe one day you'll dive into the subject. From the look of the comments here, you have all the hints you need.