I have to admit I'm much more forgiving of horror than most other genres.
For instance, I could get more out of a shitty horror film than a shitty drama or comedy etc.
There are different ages/varieties of shlock too, but most incorporate some sort of 'rip-off' quality: the countless Italian zombie and possession spin-offs in the '70s and '80s; the numerous rip-off/homage slasher films of the '80s and '90s; the modern day rip-offs of bigger budget horror franchises; Syfy/The Asylum 'creature feature' offerings. You just have to find your 'shlock niche' and go from there. As above, everyone has their own opinion on what constitutes schlock and how they define it... it all comes down to personal interpretation, and above all enjoyment.
Plus enjoyment tends to be the key in what an individual classes as shlock or just plain awful cinema, as 'shlock' in itself is a more endearing term
