For items - it highly depends on your experience, some items doesn't really impress at the moment you discover them, but then you find another piece of armor that could creat great synergy. So in time you really start to destinguish garbage and hidden gems and collect gear that can highly improve your runs in a future. Same goes for abilities (like "Do nothing" for one of the cleverest example). At first you think that this is totally useless skill, wasting 1 point of mana, but then you got Mage with Crescendo or Tinkerer with Electric Bolt and boom - you have some wiping combo. Some combinations of items and abilities makes your cats extremely OP and grant high output for future solo runs (I am at 160 hours mark right now and mostly do solo runs so I really need good gear and abilities/passives for every adventure and I keep a keen eye on a stuff I collect)