with whom are you comparing it ?
Barrett's behaviour became increasingly unpredictable, partly as a consequence of frequent experimentation with psychedelic drugs such as LSD.<7> Many report having seen him on stage with the group, strumming on one chord through the entire concert, or not playing at all<10>. At a show at The Fillmore West in San Francisco, during a performance of "Interstellar Overdrive", Barrett slowly detuned his guitar. The audience seemed to enjoy such antics, unaware of the rest of the band's consternation. Before a performance in late 1967, Barrett apparently crushed Mandrax and an entire tube of Brylcreem into his hair, which subsequently melted down his face under the heat of the stage lighting, making him look like "a guttered candle".<11> Nick Mason later disputed the Mandrax portion of this story, stating that "Syd would never waste good mandies".<12>
Following a disastrous abridged tour of the United States, David Gilmour (a school friend of Barrett's) was asked to join the band as a second guitarist to cover for Barrett as Barrett's erratic behaviour prevented him from performing. For a handful of shows David played and sang while Barrett wandered around on stage, occasionally deigning to join in playing. The other band members soon tired of Barrett's antics and, in January 1968, on the way to a show at Southampton University, the band elected not to pick Barrett up: One person in the car said, "Shall we pick Syd up?" and another person said, "Let's not bother" (Gilmour interview in Guitar World - January 1995). They attempted to retain him in the group as a songwriter.
There are many stories about Barrett's bizarre and intermittently psychotic behaviour — some are known to be true. According to Roger Waters, Barrett came into what was to be their last practice session with a new song he had dubbed "Have You Got It, Yet?". The song seemed simple enough when he first presented it to his bandmates, but it soon became impossibly difficult to learn: while they were practising it, Barrett kept changing the arrangement. He would then play it again, with the arbitrary changes, and sing "Have you got it yet?". Eventually they realised they never would and that they were simply bearing the brunt of Barrett's idiosyncratic sense of humour.
http://en.wikipedia.org/wiki/Syd_Barrett