Well I dunno, it's no different than me saying weed creates a happier feeling but heroin makes you feel better.
The way heroin makes one feel better is in regards to pure, raw tactile pleasure, or what I'd consider euphoria. Do a speedball and one will literally be crawling on the floor due to the overpowering euphoria.
Weed makes me laugh at stuff and think music sounds bomb, but as far as that deep down pit of the gut feeling of fucking astounding awesomeness it just doesn't so much have it.
Ultimately we're dealing with subjective labels here, but I'd say describing something as making one "happy" is probably a little closer to making one "giddy", where as making one "feel good" is probably close to making one "euphoric". There's a lot going on behind the scenes with a lot of complex neurobiological processes, so it's to be expected that people wouldn't always be able to put a really solid label on how any given thing makes them feel.