The mistake in this Python code is that the if statements are missing the variable name that they should be checking. The correct syntax for an if statement is `if condition:` where `condition` is some expression that evaluates to either True or False.
Also, the values `sad` and `happy` are not defined as strings in the code, so the comparison with these values will result in a NameError.
Here's the corrected code:
emotion = input("How are you feeling today?")
print(f"I'm feeling {emotion} too!")
if emotion == "sad":
print("I hope you have a good day.")
if emotion == "happy":
print("Me too.")
Note that I've added the variable name `emotion` to the if statements, and defined the comparison values as strings. Also, I've added indentation to the print statements so they are executed only when the condition is true.