It was an ugly, horribly designed, difficult to program for, overpriced, breakdown prone POS with a terrible menu system, horrible load times, and the most hyper aliased graphics in the history of video games. Until the 360 came around, the PS2 was head and shoulders above all other systems when it comes to breakdowns and read errors. I had never seen a system actually shove its laser lens right into a disc and ruin it until I saw the PS2 do it.
Why the hell do I have to go into a menu and turn the optical port ON? Why does it have half the VRAM of the Dreamcast? Why does it have two power buttons, both of them f*cking stupid? Why do most of the ports of older games look so f*cking blurry?
However, even though it had maybe two good games in its first year and a half of existence, by then Sega was broke and the self fulfilling prophecy (that is, "The PS2 will be awesome, dude!") had to be fulfilled. With only Gamecube-era Nintendo to compete with the selection of games for this system ended up being absolutely amazing, which made the system far better than it ever deserved to be.
So its amazingly wonderfully great...but its also a huge piece of shit.