Of course, if you add a timezone, you are likely in trouble when daylight savings time comes/goes. That is, shows don't change times just because you effectively changed timezones.

Depends on how you're storing the timezone. If you store it as "UTC+2 hrs", then yes you'll have a problem. If you store it as the tzdata "Europe/Sofia", then it'll take care of all the timezones.

I, of course, can not disagree. Just wanted to add to the voices that point out much in dealing with time in computers depends on your goal.