getting psyched before a lift is one of the most important things you can do - some people just have different ways of going about it. studies show that doing so before benching increases your max by 12% (thanks Flex magazine).
whether its growling and saying "Common Haney! #1", having Leroy Davies yell at you to "let's go diesal-man - time to get nasty now - nice chunky movement", or yellin "yeaaaah buuuuddy!" do whatever it takes.
sure slapping your head for a 135 max bench is a bit much, but i'd rather train at a gym with that kind of intesity going on than some fitness spa. Personally, a good slap on the back ala Cost of redemption gets me going for heavy squats - makes the bar "dissapear"
to each their own