Naïve is what usually gets everyone into trouble since you have no frame of reference and you need to do all kinds of magic to try and deduce timezones and adap

Naïve is what usually gets everyone into trouble since you have no frame of reference and you need to do all kinds of magic to try and deduce timezones and adapt to it. It also makes it utterly impossible to properly deal with DST changes etc. unless you know that everyone using your system is coming from the same TZ. I don't like the default of UTC either though. Explicit is better than implicit, so make people always specify a timezone instead which avoids all form of ambiguity.