Compensation

Thinking about compensating his neighbors, he deliberated on ordering three normal-sized pizzas but ended up ordering only two.

This was because he didn't think Ray would be too welcoming about this kind of gesture, considering matters relating to his pride and boundaries.

He considered specifying that it was for Emily, but then again, Emily was Ray's wife. Giving her such a gift out of the woodwork right after Ray caught Lenny in his apartment with his wife—briefly disregarding the fact that absolutely nothing of that sort occurred, and coupled with his knowledge of Ray's current predicament, Lenny's innocent gesture could mean an entirely different thing.

Therefore, he respected himself and decided to repay Ray and Emily for partaking in the experiment after they had settled their differences.