It depends, i lost interest in Red Dead Redemption, mostly cuz i got pissed off with trying to kill a bear with a freakin knife, silly stuff like that always happens to me when i play games, only for me to come back to it later... unless i start playing something else and completely forget about it.
Also, i haven't "finished" Dead Rising 2, i usually end up slaughtering zombies for 10 minutes when i feel like i need to vent and forget about the cases. And i have a pile of JRPGS i have hardly played, i find them very hit and miss, some i play through in insane marathon sessions and others i quit an hour or two in.