Even or Odd

I got gas this morning. Nothing so spectacular about that. But I have this thing when I get gas - the amount has to end in either a 5 or a zero. So, I never have an amount that is $42.37 - it would either have to be $42.35 or I'd go up to $42.40. I don't know when I started doing that. But funny thing is, Sarah was with me once and I said to her - the total has to end in either a 5 or a zero and she was like - duh, of course. So is it generic - these little quirks we have??