The good: * Semi euphoric floating sensation * Everything is hilarious * Feeling of connectedness & significance of otherwise insignificant things * Otherwise boring things seem fun & novel * Food is amazing

The bad: * Euphoric floating sensation is short-lived and chasing it by redosing has nowhere near the initial effect * Paranoia and anxiety levels heightened * Mixes well with alcohol if the proportions are correct. If not it's a sickening hell * Inability to concentrate on any moderately complex task *As the effect wears off you're still too high to do anything but the fun part is over so it's tempting to redose and waste more time * General lack of motivation to do anything * Unlike alcohol there's no (or very little) painful hangover so continuous daily use is very easy to slip into

I could go into the effects of long term heavy use but that's not what was really asked here and it also varies greatly between different people.