I'll tell you mine. Bandleader's Chinese made Ampeg 4x10 that I played through tonight. Couldn't get a decent sound out of it running my Stingray into a Mesa Subway TT-800 head no matter what I did. Absolute rubbish.
Yours?
That would be the GK 115bpx cab that I bought in 2006. I had actually used a GK guitar amp in 1997 to play bass into a couple of JBL 112 with wide horn speakers that really sounded good. So their "Brat Pack" was on sale and I bought it with high expectations. The amp that came with it was also crap. It was a GK Backline 250, which I thought was 250-watts. It was 250 PEAK watts, dp 125-watts rms, AND it could only handle a minimum load of 8Ω. That combo put out the muddiest sound I could imagine no matter how I set it. When we gigged and went through the sound board, the sound tech could clear out the mud it produced either.
I used it with a 4Ω Sunn B202 (212 that handles 100-watts) cab I had that had both serial and parallel outputs from the cab and by using the serial output, that allowed me to use it with my Sunn cab because serial outputs add up the ohms instead of reducing them. So the watts went down from 125-watts rms to about 85-watts rms but the extra 24" of speakers made it a little louder and sounded a lot better. Still not great, so bought an Eden Nemesis RS400 (400-watts rms) which is a great sounding amp. Unfortunately that caused my Sunn cab to make farting sounds very easily, so bought an acoustic B410 when GC first brought them out. Sounded better but still had to drop the bass EQ to 10 o'clock to clear up at least some of the mud.
Then, in bought my WT500/800 (bridges at 800-watts into 8Ω or 400-watts into 4Ω per channel). It has two power channels so hooked the 410 up to one side and the GK115bpx up to the other. Then used the balance know to send more power to the channel with the 410 and it sent less to the 115. That finally tamed that boomy cab without sacrificing the normal bass EQ for that "starving-for-some-bass-EQ" acoustic B410. Gigged that for another 5-years, until I moved to Washington. My DNS-410 (by DNA) arrived 2-days before we moved from Virginia so I didn't get to play through that until we got here. Then, by itself, it was louder than and much better sounding than my 410+115 stack.
I had both that acoustic B410 and that GK115bpx listed on the classifieds here for a few months but finally just donated them to a local church, who was very happy to get them. So I had that cab for almost 10-years and was ever so glad to get rid of it. Now, I have used GK gear that sounded quite good and worked quite well, but that bottom-of-their-line GK-115bpx was by far and away the worst cab I'd ever had.
The GK "Brat Pack":