Two scents that go from 0 to 100 real quick:  Patchouli and tea tree oil.  I didn't realize what patchouli was until someone pointed out to me it's what every live music event, hippie, and health food store smell like.  I don't mind the smell, but there seems to be no reasonable amount of it.  It's either absent, or there's a gallon of it invading your nasal passages. 

Tea tree oil has the same effect on me.  Maybe it's just me, but there's no acceptable amount of tea tree oil scent.  It has the very weird effect of making me feel like I can taste it, even when I'm quite confident I didn't put it in my mouth. #lifestyle