As a pedantic native English speaker, the name "WhatsApp" has always irritated me somehow. It's just not nice. There's an apostrophe missing, it's two words with intermediate capitalization and no space, "App" in the name of an app is redundant, the "pun" is a bit dumb (does it even really qualify as a pun?)...

But it's clearly worked out well for them, so I guess it's a good thing people like me weren't involved in their naming. shrug