The only reason you shouldn't get it is if you're allergic to eggs or if you actually want to get the flu. You may get folk saying it's useless and it won't protect you against flu, that's true, there's a 1 in 5 chance it may not protect you against this years strain of flu if it's mutated enough, but personally, there isn't a single reason apart from if you're allergic that would stop me getting it. It will save you a mountain of hassle if it does protect you. Our immune systems are compromised by diabetes so it makes no sense whatsoever to not get the flu jab.