This is how it feels for me, I wonder if others feel the same way.
In the early days of quitting it is all exciting and new. You start off by counting the hours and get excited by the prospect of new milestones etc.
As time goes on being smoke free becomes normality, and I think that is why many people find they slip up after 12 weeks or so. Keeping the resolve going becomes more difficult and that is why the right frame of mind is essential.
I've tried to convince myself that there is no enjoyment to smoking, but that doesn't work, I know that the enjoyment is minimal, the vast majority of cigarettes did not give pleasure just relief from withdrawal and you can not experience the odd one here and there, you have to take the 99.7% of crap to experience the 0.3% of buzz.
Over time you forget the cost of the 99.7% in terms of health, wealth, acceptability and slavery. Not smoking is the norm but you miss the old days when it was so much part of you and feel that some how you are on your own in dealing with everything. OK the use of cigarettes in the past was basically to relieve the cravings that built up since we had the last smoke, but we spent so long with the perception that they somehow helped that it is not easy to shake the idea now.
The most important thing for me to remember is never think I can get away with just one. I know because I am experiencing it that the temptation to "cheat" is bubbling under the surface, it must not be allowed to break through, I can not mess this quit up like I have done so many in the past, and I will not.
Getting and keeping the mind in the right place is not a one stop deal it and needs regular work to maintain it, and that work will be done!