Elder Scrolls: Oblivion ... leveling up skills is absurdly tedious and boring. Autorunning into walls for hours on end, using tape to hold the jump key down or spamming some useless spell till out of mana (magicka) then resting for an hour and repeat ... tedious and boring. IMO any gameplay mechanic that actively encourages you to let it play without you at the keyboard is a poor decision
Also the voice acting is possibly the worst I've ever heard in a video game (for everyone except Cap'n Picard.) Accents will change mid dialog, attitudes switch from cheery to gloomy and all over the place from sentence to sentence.
And for min/maxer's, the leveling up process is actively detrimental. Getting a character with one or two maxed out stats (not looking for complete 100s down the board, but the primary stats) takes active planning and a separate notepad and excel spreadsheet.
All that being said, still a great game, and one I've dumped well over a hundred hours into.