Yup, I noticed it tends to flare as compared to my kit lens set at 50mm when the aperture are opened wider, and this is the very reason why I bought this lens.. to use wide open aperture for background blur, which is almost impossible with the kit lens maximum ap at f5.6 @ around 50mm
Why don't you make yourself a lens hood? Free templates are available for downloading from www.lenshoods.co.uk for most of the common lenses. You can actually make the hood out of reasonably stiff but pliable material and have it painted black and it is just as good.
Hey man I bought a canon 50ML myself and its beyond me why Canon do not supply a lens hood when u buy their lenses. I refuse to go and spend 40-50 Aussie dollars for a genuine one so i bought a rubber one that screws onto your lens thread.
One qtr of the price.