There is a famous "scale" of heat for peppers - the "Scoville Organoleptic Test" (
http://ushotstuff.com/Heat.Scale.htm). It lists the naga jolokia as definitely hotter than the red savina habanero, but still not as hot as the capsaicin, which is still the hottest there is. Capsaicin, as we know, is the pepper used for defensive pepper spray.
Besides, as shown in an accompanying link on that page, the measurement of heat is dependent upon environmental and climatic factors, and can change in even one pepper from year to year, and harvest to harvest.
Personally, in spite of my part-Italian ancestry, I hate hot stuff. Especially REALLY hot stuff. I find anything approaching even a chipotle (which is insufferably hot to me) to be way too much. That, and knowing that the juices from a pepper can actually
destroy the taste buds on your tongue (thus part of the pain factor involved) AND produce stomach ulcers if eaten in enough frequency, I prefer to err on the side of caution and sensibility. lol