Just stating that oil or hydraulic fumes used to be very common in older aircraft W/O a huge reaction. Being a freight dog it was quite normal, if bad enough for us to encounter fumes that were more than a simple discomfort greater than a crew member asking to pull his finger we usually changed the ACM socks as they would accumulate the contaminants. Modern aircraft (have not dealt with this problem for a decade or so) are much cleaner.
The worst case I experienced was on the ground where the ground/flight crew failed to turn off the environmentals during deice. We pressurized and dumped the cabin 3 times before everyone was comfortable in taking the flight. The second was a flight of several hundred pigs that died in flight, I had to was all my clothes 3 times after taking the aircraft after it's fourth leg. Then the Hajj flights, Hell we were expecting the smell and were all used to it after about 3 days.
Point being, fumes and discomfort in smell are a human factor. This thread makes me feel old. Not stating that anyone here is spoiled in comfort, just that the perception of what is acceptable has changed greatly from the above reactions over the years.