The hot, humid climate has taught Hawaiians to dress lightly and casually. You won’t see a local woman in heels or a man in shoes – only tourists wear that.
The islanders wear rubber flip-flops or light sandals. You can even come to a fancy restaurant in shorts and flip-flops, and no one will bat an eye.
Hawaiian shirts are really in high esteem here, they are worn with or without a reason. A colorful shirt and slacks are already a full-fledged business style.
Also, locals don’t wear slippers around the house, they may not put on shoes before going outside and, for example, go to Starbucks for coffee barefoot. And why not?