I think you have to have real poor judgment if you can't decide whether you like a game or not early on. I don't typically buy games that I haven't researched or set proper expectations for. So if a game has a slow start and then gets good some hours into it, I would be aware enough to know that going in.
A game would have to be either really poorly made, extremely bland, or just flat out not my thing for me to put it down and never look back and I've put up with some stinkers. Which is why it's important to clarify what exactly makes you hate a game.
For example, I hate Resident Evil 7 and Village. I think they ruined the series in pretty much the same way Resident Evil 4 did in 2005. Yet, I've played and enjoyed all these games to varying to degrees because they're well made games I would be inclined to praise more if they weren't called Resident Evil.