These are probably the reasons everyone else stops, but here goes!
I'm fed up with being addicted to it, used to really enjoy smoking but know I was only doing it to stop me getting angry and grumpy.
It's expensive, I used to spend nearly £8 a day on cigarettes, and the extra money is going to come in handy!!
I don't like the smell. This was the trigger for me - a bit odd but bear with me lol. I bought a new bag, popped my ashtray pouch in it 'cos I was going out then opened my lovely new bag and *blech* it stank. Don't know why it hadn't hit me before, then I sniffed my hands and hair and could smell cigarettes.
That was sort of my "moment" when I knew I was ready to stop!!