Python 2, 97 95 92 90 bytes

for i in range(input()):
 for w in'Yeah','But','No':
	if(len(w)<3)==i%(3-len(w)%2):print w

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Python 3, 92 90 bytes

def f(n):[print('Yeah\n'*(i%3<1)+'But\n'*(i%2<1)+'No\n'*(i%3==1),end='')for i in range(n)]

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_{-2 bytes, thanks to ovs}