The curse of sample-based trackers - you assume that samples must sound better, because they are actual recordings of real instruments, but you can still get bad samples. The worst thing is when they're out of tune! You could only get an out of tune synth by doing it on purpose. And then having to squeeze those samples down so your mod will fit in 512k of Chip Ram alongside all of the rest of the game, so you reduce the sample rate and get horrible aliasing, and/or you shorten them too much and loop them badly so they go "dingdingdingding" or "pop pop pop".
The irony that so many good mods made liberal use of 64-byte waveforms, vibrato effects and arpeggios...
However, now there's dubstep...