I had flu once twenty years ago. It very nearly killed me and left me with worse Asthma than I had before. I have the jab every year and apart from a sore arm some years I have had no issues.
My missus has the jab too as she has a lung condition and flu would almost certainly would finish her off. Even a cold has landed her into hospital with pneumonia, twice in the last 9 years and both times were enough for me to fear I'd lose her.
Having/not having the jab is an individual choice but one thing is certain for some of us it's a life saver. As has been said before in this thread you can't catch flu from the jab, it isn't that kind of vaccine. Although I understand some people are allergic the eggs, used as a growth medium for the vaccine, and can be ill after their first jab, but not because of the flu.