I mean they are necessary for some people..
Not sure about eating them
Depression or being alone with someone of the opposite or same sex for longer than like 10 minutes
Communication is key in a relationship. This can help them talk through their problems
Effectiveness and safety?
Explanation:
A thermos flask has double walls, which are evacuated and the vacuum bottle is silvered on the inside. The vacuum between the two walls prevents heat being transferred from the inside to the outside by conduction and convection.