I was camping recently and someone was complaining that they were finding it hard to sleep, as their new self inflating mat was much more slippery than their old foam one.
Is this a real effect, and why does it occur?
Is it a general feature of self-inflating mats vs foam, the particular design, a factor of age, or are they just imagining things?
To be fair we were camped on a fair slope, but no one else had this problem (or at least didn't complain about it).