Jokes on you, my Excel regularily thinks that two cells are not equal, despite both of them having exactly the same value and type (also no trailing spaces or these things). Copy and pasting it around sometimes solves the problem, but it never is apparent to me why that happens.
other than that, I agree with the other poster and the only issue I can think of is due to having a different number of digits after the decimal point causing some rounding error when comparing floats