No, Unless You have had a problem with this before,NO
No, you should not be worried. It is fine.
No, header gaskets don't need any sealers on them.
Does the friend has the history of stealing. If he does then you should be worried, but if he does not you should not be worried. But to be safe, you can keep you stuff on safe place to avoid excuses.
Yes, you should be worried if it was not caused by mosquitoes or falliing.
My friend, the whole world should be worried about Global Warming, including you.
should i be worried about this bump at the corner of my right ears?
Depends if you want to be pregnant. If not you should be worried...
you should be some what worried because that could mean that you are not socializing him properly.
You should never be 'worried' about girls. They are not dangerous, unless you lack self-control.
The most dangerous type of radiation is Nuclear radiation which is the one that should be most worried about.
Theoretically, under normal operating conditions, and proper maintenence, intake manifold gaskets should last for the entire life of the vehicle. To my knowledge, there is no prescribed routine replacement interval for intake manifold gaskets. Of course anytime a head(s) is removed, then new gaskets should be used in reassembly.
At 5'7, you should most certainly be worried.