do you tip at resturants?

I tip according to SERVICE,ATTITUDE,ETC! If the service sucks and theattitude is crappy then so is the TIP! On the other hand if all is good then the TIP is also. I also tip others that help with the service,sometimes when waiters or waitresses are swamped some others will assist in refilling tea,bringing food etc so I make sure they get a little something also. I make it a point to thank them and put it right in there hand to make sure they get the tip.