The closest I go to fast food is non chain pizza joints. Fast food is gross, the food quality is poor, the sanitary conditions in those places are poor, the taste is poor, and to top it off you feel like crap after eating it. People who gorge of fast food are also gross to look for the most part.
My choice for fast takeout is a small family run Lebanese restaurant that that makes the best wraps I've ever tasted.
I use to work as a Pizza maker and I can honestly tell you big Pizza chains and privately owned Pizza restaurants are pretty much just as dirty, even the fancier looking Italian type family Pizza restaurants are no cleaner (I'm not talking top rated super expense restaurants though) at least that's the case in Toronto, Canada where I live.
But even if the place is a bit unsanitary and the food is cooked properly and thoroughly there should be no way germs/bacteria can withstand temperatures beyond 60 degrees celcius, this is the main reason why they reheat Pizza slices regardless if you ask or not.
In terms of Subway or Mr. Sub (Canadian) being fast food or not it's debatable (it's healthier) but IMHO anything under the category of process meats, fried, washes down better with sodas, greasy, precooked and kept warm or reheated (during rush hours) and comes with fortune cookies is fast food to me.
With all that being said even having worked in the back of a fast food restaurant in the past and seen lots of screwed up things some fast food workers can do to your food, I still love fast food and have to go get some every now and then to satisfy my cravings.
PS. Be polite and nice to people who serve you fast food, it goes a long way.