The most common wireless networking problems with MacBook's macOS Sierra 10.12 is either randomly dropping Wi-Fi connections or an unusually slow or delayed Wi-Fi experience.
The temporary solution to this is to refresh the en0 (Wi-Fi) network interface silently in background. The code below will refresh every 30 seconds.
Open a terminal and copy and paste this bash code below and hit enter:
while true; do echo "add State:/Network/Interface/en0/RefreshConfiguration temporary" | sudo scutil; sleep 30; done;
Note: The command above requires admin (sudo) rights to your machine and you need to type in your password.