LPT: when receiving a call from an unknown number, don't answer it silently and pretend to be dead like a weirdo; just let it go to voice mail. If it's important, they'll leave a message.

Spam bots will often reveal themselves through voice mail as well. If no message is left, it must not have been important.

You'll also avoid coming across as a serial killer when that potential employer calls you about an interview, only to be met by silence and breathing when you answer the phone.