Evernote and Whatsapp are the two most important apps on my phone, in that order. I put whatsapp in second because I can reach the same people on Facebook, regular text messages and phone calls, Skype, etc, but there's no similar tool to Evernote that does what it does with nearly the same level of efficiency. I use social media daily, but 90% of it is either my game studio's social media accounts, or my media company's social media accounts.
I use Apple Music and the built in podcast app a lot, but those are pre-installed, so I don't know if they fit into this discussion.
If you're curious, the companies I referred to are
http://illuminaregames.com,
http://taoofotaku.com
and http://kugali.com
3DS: tolu619
Wii U: FoyehBoys
Vita, PS3 and PS4: FoyehBoys
XBoxOne: Tolu619
Switch: Tolu619
Kugali - We publish comics from all across Africa and the diaspora, and we also push the boundaries of Augmented Reality storytelling. Check us out!