Depends on your vehicle. For my Focus, almost any oil is good oil. Its a proven KISS port FI NA engine with no bad design decisions, or poor parts suppliers, and it lives the ideal life spending most of its time at ~2400 rpm, ~55mph for ~30 minutes at a time with the engine at 200f...Are there actually "bad" oils available to buy on store shelves (in the US) ?
These can and do go well over 300k miles with iffy-lube conventional 5W20 every 5k, and white box filters, with the odd forgotten oil change.... For the last couple years I'm doing ~12-14k mile OCI's, as its quite clear the engine is going to outlast the body by a long long margin! I need to add a litre in the middle somewhere to get to the end on the low mark, and it gets whatever is handy, 15W40 last week so I could empty the pail.
Iffy-lube, cheapest supplier they could find bulk 5W20, probably isn't going to work in something with the lightest possible tension rings, or more complicated with DI and turbos, and 17' of timing chains and VVT hardware, running much hotter or colder(if you short trip), with potential dilution issues or LSPI, and a 10k OCI.... Almost anything new these days is nearly as complicated as a 2000's Audi S performance engine, but made on a tighter budget, and not built by Hans in Ingolstadt. So oil that meets the specs or better is "cheap insurance" for almost everything now.