system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] What a hunk of junk, and other comments on the Falcon.

Nearly everyone comments on the extreme unsuitability of the Falcon upon first seeing it.  "You came in that? You're braver than I thought."  "The garbage will do."  
I know Han intends for the Falcon not to look flashy, but my question is this:  Are the YT-1300 line considered to be particularly junky ships to begin with, or is there something about the appearance of the Millennium Falcon specifically that elicits this particular response?
gpt
The YT-1300 has a rep in universe as being heavily modifiable, having enough internal space and power to handle anything you could reasonably drop into a vessel that size.

But the Millennium Falcon took it a bit too far; the engines have been tricked out virtually to the maximum, and the internal spaces have been extensively rearranged to make room for gizmos like concealed weapons, high powered point defense guns, and smuggling compartments with shielding and built-in emergency auto-ejectors. If all these mods were done in a professional shop or shipyard, this would be ok, but they weren't; Han and Chewie (and Lando when he held the pink slip) did their mods on the fly, without professional assistance and in settings that make "rough" look nice, often under significant time pressure and using components never meant for the purposes they intended.

By the time Luke claps eyes on it, they've layered mods on top of mods, jury rigged repairs to fix their previous repairs, and generally made a pretty severe mess of things.

End result? One of the slickest rides in the galaxy, when it works, and a rough looking scrapheap 24/7.