There is absolutely a difference between a game being good or bad and someone personally liking or disliking a game. Of course everyone is entitled to their own opinions, so everyone will like and dislike certain things, but there undeniable facts to consider when judging a game on objective quality.
Things like game performance, control responsiveness, voice work, and graphical quality can all be quantified fairly easily. Other aspects like level design, combat, writing and story can be a bit more subjective, but there are still genre standards of quality to judge by. While the quality of these elements can pretty accurately determine what makes a game objectively good, everyone will have their own preferences.
Take for example, Deadly Premonition. If you were to judge the game based solely on the above the criteria, it is an objectively bad game. However, many people found aspects like the characters and story, which were the game's high points, good enough to look past it's many shortcomings. Whether or not someone liked the game, it is still objectively bad due to its clunky controls, dated visuals, poor and repetitive animations, and bad level design.
To summarize, just like any art form, games can be very subjective, but that doesn't mean there aren't things about games that can be objectively good or bad. So, just because you don't like a certain game, doesn't mean it's necessarily bad, nor does your love of a game make it objectively either.