When Firebug came out it was such a big deal that it was the sole reason our IE-only product (which was not a simple application, it was fully-fledged fleet man

When Firebug came out it was such a big deal that it was the sole reason our IE-only product (which was not a simple application, it was fully-fledged fleet management, tracking, mapping, and reporting platform, entirely web-based) got cross-browser compatibility (we made it work with Firefox). Being able to use Firebug was such a huge boon to development back in the day, though it probably looks primitive today.