The Signal messenger and protocol.

Nope, don't need crap like that in my messaging app. I'm honestly still pissed they went away from working over to SMS to using their own (regularly failing) servers and then being very actively hostile to any forks and plain reproducable builds. Signal remains the most easy-to-convince-people option, but there's still a lot that looks mighty suspicious (and pointless features is one of those classic ways to hide deliberate backdoors/vulns).