I really took to Double Nickels after my friend made me a "best of" CD of the best tunes on it. That really helped me get into it; feels like a barrage of great riffs, solos and weird lyrics. They weren't much of a punk band other than the short songs. More of a funk rock hybrid and willing to try anything within the most stark and basic production values you'll come across. I don't know if that will convince you of anything, but there's a lot of jokey throwaway songs throughout the album, and if you boil it down to its most focused rock songs, it might boost your opinion of it.
Zen Arcade is tough to get into as well because it's likewise very long and full of weird interludes. But if you don't like the harshness of the sound, you'll only get a few reprieves. For my money, the hardcore songs are some of the best of the genre (particularly most of the Mould songs on the first half like Pride and I'll Never Forget You). But if tortured hardcore punk is not your thing, the few poppier songs might not make a difference.
It's tough for both of these because they're generally seen as the two bands' respective best releases, but for a newcomer to either group, it's a lot to take in. I think both albums would be enjoyed a lot more after becoming familiar with other releases by each.