Usually I wait for bug fixes to be released, not too biased reviews to be written, other gamers to give their verdict and prices to drop before buying a game, so I almost always get what I like, but in a few cases I couldn't continue playing or even start them due to bugs or HW incompatibilities, luckily they were from bargain bins, a few other times I stopped playing because for my tastes they were crap and of the most recent games I stopped playing I'm not very willing to continue only one, Temple of Elemental Evil, that I didn't reinstall when I upgraded WinME to Win2000, because I feel it would be too inferior to the others I want to continue and to Planescape: Tormen I'm currently playing, but I'll need some time and reading some walkthrough up to where I left them to avoid restarting from the beginning, as too much time passed and I lost the thread of their plots/quests.
And usually I like to play 100% of the games I like, without skipping subquests, and exploring levels completely (obviously this helped me getting lost in Morrowind 
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