Gmail Filters: Apply 1 Filter to Multiple Email Addresses/Senders

Problem: You don't want to create the same filter multiple times.  You want a set of actions to be applied to multiple email addresses AAA@gmail.com, BBB@gmail.com & CCC@gmail.com

Solution:
Enter {AAA@gmail.com BBB@gmail.com CCC@gmail.com} using squiggly brackets

Thunderbird won't let you access your Gmail account

Problem: You're trying to set up your Gmail acct in Thunderbird, but it won't accept your username/password and keeps asking you if you're sure it's correct.

Solution:
https://www.google.com/settings/security/lesssecureapps → Enable → Try logging in w/Thunderbird again