This kind of software is what I lump into the category of "just give me regular expressions". There's so many interfaces that would be simplified by (hard!) standardizing textual abbreviations and providing something powerful like regular expressions.

I'm currently shopping for expansion PEX (a.k.a. F1960) fittings and it drives me up a wall when all you want is sizeA: 1", sizeB: 1", typeA: F1960, typeB: MNPT and all you can use is a free text query. Search for '1" F1960 MNPT' or equivalent and you get back all kinds of things that have nothing to do with what you searched for. That's par for the course when businesses don't have what you want and they're trying to give you anything to not have zero results -- but in this case they do have the parts, their crap search just doesn't return them. Try searching for PEX-A vs PEX-B at Home Depot and it's clear many people will accidentally buy the wrong thing.

Airline searches (for me, at least) were very similar. 99% of engines would not give you results spanning across two tickets (no codeshare agreement) or take into account human factors. More recently, search results started to show "pain factor" mostly as an amount of connection time or overall trip time. That (again, for me) is not pain -- pain is connecting in LHR or CDG when you could connect in VIE or WAW. Or worse, getting some flight pushed in your face on a single ticket that has a LHR/LGW transfer vs. two separate tickets in a much smaller airport further east. Similarly, why not offer a plane type filter on every search? Pain is flying on some 20-30 year old airframe on a big airline instead of a Dreamliner on a smaller one. (LOT, if you're interested... :))