Text:

“If you have sandals and you put the sandals on the ground upside down, its a bad thing. It means you are disrespecting God. This is for any shoes, it’s disrespect. I learned this when I was little. I don’t care anymore, but some people believe that.”

Context:

The informant learned this in childhood, and said it is a very common belief, and attributed it to the Muslim majority in Turkey.

Analysis: 

In Islamic countries (and Muslim-majority Turkey) shoes are considered dirty because they touch the ground which is unclean. To turn the bottom of your sandal or shoe upwards, towards God, is to show him disrespect. The informant no longer cares, demonstrating secularization, but there is belief negotiation – they respect that others, many not Muslim, abide by it.