I guess for me it was Yoshi´s Story for the N64.

Yoshi's Story: took the words right outta my mouth. It's one of the few Nintendo games that I didn't care for, along with every Mario Party game that I've played.

New Super Mario Bros, it was way to easy for a mario game.

In the "out of left field" category:

Teenage Mutant Ninja Turtles: Fall of the Foot Clan for Gameboy.

I remember being heartbroken after buying that game and beating it in an afternoon. I was only 13 or so at the time.

Donkey Kong. 3 easy levels

That comes to mind right way? It would have to be Paper Mario (N64). Repetitive battle and virtually 0 chance of ever dying kinda kills it. Not that I didn't like it though, oddly enough.

Alladin for the SNES, for some reason (don´t ask why I have no idea) we rented that game when it came out and finished it in two hours... what a dissapointment, the visuals where pretty good for the time but you could almost run through the entire game without a problem... and we were kids back then.

Played through Commander Keen: Enters the Shadow Lands recently... it wasn´t easy but when I was a kid I thought it was insanely hard... now its hardly a challange... still I love Commander Keen, one of my childhood heros.

Oh and eventhough I find the co-op in the Lego Star Wars games fun I must say... is there even the possibility to lose ??? Those are easy as hell... 

Legend of Zelda: Twilight Princess.

The most difficult part of the game was walking through the boring desert.

Yeah, both New Super Mario Bros. and Twilight Princess were easy.

Super Paper Mario was also easy.

Pong.