On Over/Under Bets and Liquidity in Resolution

Been looking at some of the over/under markets on Polymarket lately, especially those with very clear resolution criteria like a specific price point hit. It seems like there's an inherent edge in taking the 'under' side when liquidity is thin, especially on things that are already hovering near the threshold. The logic is, if it's already near, the 'over' side will likely attract more attention and push the odds further. But if it doesn't quite get there, you're looking at a decent payout. I've seen it play out on some $AAVE price predictions where it just couldn't quite break a certain level, like if someone set an over/under at say, $95 when it was hovering around $94.34. The initial push might get it close, but the follow-through often isn't there, and then the 'under' pays out.

Am I missing something obvious here? Is this just a simple case of human psychology overestimating momentum, or is there a flaw in my thinking? Curious to hear some pushback from the room.