I was having troubles with my TV service when this started so I sadly missed out on the start of the show but around season two or three, it was quickly becoming too popular to dismiss.
I've watched it regularly since around late season three or early season four. It was not long before I fell in love with its original brand of comedy enough to keep an eye out for sales on the series.
Going thru the first three seasons revealed that I had seen almost all of them thru re-runs. Even if they were confusedly out of order.
This series is a bit unlike the wacky comedy sitcoms I usually like such as Scrubs, Titus, Malcome in the Middle, & Big Bang Theory but perhaps that has helped it since I don't know if any of those shows won any Emmy Awards let alone four of them.
Sadly, it seems it's the more "realistic" sitcoms that become the most popular.
Regardless of which way you lean, I would highly recommend checking this out.