So, do you slip a stitch purl wise unless otherwise indicated in the pattern? 
That has always been what I was told so I stick with it. 
I always slip purlwise, UNLESS it’s for a decrease, such a SSK. I find that for SSK it lays much flatter when you slip then knit-wise.
lol I do that too but whenever I say stuff like that someone tells me I am doing it wrong (which is why I rarely answer these questions anymore truthfully) so I am glad to see someone else saying it.
That’s exactly what it says to do in Vogue knitting, as I recall. 
(and yeah, it’s what I do to!)