When ordering pizza delivery with some friends recently, the topic of tipping came up. I was ready to tip 18%, but I got a lot of "are you crazy!" reactions. I rarely order delivery so I wasn't that confident in my tipping approach. And maybe for good reason. Looking back at past Slice posts on the subject, it's clear that while the convention of tipping is widely accepted, people have greatly varying interpretations of what constitutes a fair tip.
For the purposes of this poll, assume you are ordering from a place that doesn't tack on an additional delivery fee. Based on an average delivery experience (no special circumstances like inclement weather), what's your baseline approach to tipping?