Overall, I like the *premise* of this series a lot, although the writing itself isn't truly stellar.
Story 1 was very meh. The boss never really noticed his employee until after he received the letter so that made it hard to invest or believe in their instalove story.
Story 2 was weird. I don't mind stories where the sexy prof falls for his hot TA, but this one just felt strange somehow. The couple didn't have much chemistry either. Worse, I didn't like the heroine.
Story 3 was pretty good. The hero sounded super sexy, like my perfect guy. I thought he & the heroine had an easy, natural dynamic.
Story 4 was the best one by far. I am a sucker for a good friends-to-lovers tale, and this one hit all the feels in a few very short chapters. The chemistry between the lovers was good. I liked them together.