Pretty much everything, but for me the two biggies were field service & avoiding holidays..
Field service--when I am truly honest with myself, I have to admit that even at my most fanatical I never considered it 'natural.' Going to strangers' doors for ANY reason has always made me nervous, but doing so to present a message that you KNOW will not be well-received is CLEARLY UNNATURAL. Try doing it in the middle of a Tucson summer when it is approaching 100 degrees by 9:00 am, or in a territory where you ran into kids from school (the teasing that would follow on Monday...)
Avoiding holidays (or the flag salute)--always hell. No matter how much I thought I was 'pleasing Jehovah,' or how many times my parents went over the 'School' brochure & told me the things to parrot back to teachers or schoolmates, being laughed at as I sat on the sidelines or left the room was NEVER NATURAL...
DesertRat