Program does not print a good guess.

import random

words = [
    "bmw", 
    "mercedes",
    "volkswagen",
    "opel",
    "maybach",
    "porsche",
    "jaguar",
    "rolls",
    "maseratti",
    "ferrari",
    "lexus",
    "toyota",
    "lada",
    "seat",
    "ford",
    "skoda"
]    
# make a list of words

# draw spaces
# take guess
# draw guesses letters and strikes
# print ou win/lose

while True:
    start = input("Press enter/return to start, or press Q to quit: ")
    if start.lower() == "q":
        break
    # pick a random word
    secret_word = random.choice(words)
    bad_guesses = []
    good_guesses = []    

    while len(bad_guesses) < 7 and len(good_guesses) != len(list(secret_word)):
        for letter in secret_word:
            if letter in good_guesses:
                print(letter, end="")
            else:
                print("_", end="")

        print("")
        print("Strikes: {}/7.".format(len(bad_guesses)))
        print("")

        guess = input("Guess a letter: ").lower()

        if len(guess) != 1:
            print("You can only guess a single letter.")
            continue

        elif guess in bad_guesses or guess in good_guesses:
            print("You've already guesses that letter")
            continue
        elif not guess.isalpha():
            print("You can only guess letters")
            continue
        if guess in good_guesses:
            good_guesses.append(guess)
            if len(good_guesses) == len(list(secret_word)):
                print("You win! The secret word was {}.".format(secret_word))
                break
        else:
            bad_guesses.append(guess)
    else:
        print("You didnt guess it! My secret word was {}.".format(secret_word))