The first one became evident during the first six months in our new church: never put a lavatory next to a confessional. There is something wrong with hearing a flush while giving absolution.
As for number two, expiration dates on sunblock should actually be taken seriously. Previously I discovered that if sunblock freezes, the active ingredient separates. (This leads to a tiger stripe effect.) But while sailing last week, I found out that the active ingredient can become passive over time.