Hello
I think that the very fact that we actually go ahead with the whole ivf process in the first place is because, somewhere maybe in the very depths of our souls, we have some hope & positivity that it may work. the not so positive feelings during the process and during the tww i think is, for me anyway, a protective mechanism - so that if it happens to be a neg result then we might not have as far to fall. I dont really think having particular neg or pos thoughts is going to affect the outcome, but i am a believer that positive thoughts are going to be healthier for you in the long run. I usually sit in the middle, neutral/realist...but try will all my might to lean on the positive side!!
Best of luck to all of you