60Hz vs 120Hz (Refresh rate anxiety)

Got a great deal on a 50" LED 1080P TV but the refresh rate is 60Hz and now I keep looking in the rear view and wondering if I should return and get a 120Hz or even 240Hz tv.

Is this a relevant concern or am I reading too much Verge and being brainwashed by CES 4ktv porn?

Is any content actually shown in 120Hz? If so, what kinds? Blu-Ray? TV? PC?

If so, is the difference noticeable?

Seeing a lot of contradictory info online.