Because he "feels anger," rather than "feeling angry." It is not reflexive to feel anger because he is actively feeling something (anger); it's a direct object of the verb. When he is feeling angry, it is reflexive upon himself. He is "feeling anger on himself," causing him to be in the state of angry.
On czuje złość, ale on czuje się zły, even though the latter means "he's feeling bad."
This is hard to explain. I hope it makes some kind of sense, since English doesn't use this type of construction.
That's a very good explanation, however if I understand "he's feeling bad" correctly (he's feeling unwell), that would be "On źle się czuje/czuje się źle".
"On czuje się zły" sounds to me as "He feels that he's evil" or something like that. Maybe angry.
Oops! Hahaha! Yes, by "bad" I meant "evil" rather than "unwell," which would be "badly" in proper grammar. I should've chosen my words better. Thanks for that
Why couldn't it be he is angry and shy beacause shame is not exactly the ssme as shy and you wouldnt say i feel shame you would say i feel shy