Tailored motivational messages are often used in eHealth applications for behavior change. However, they are often hand-crafted and without a specific structure, which makes it harder to reuse, reproduce, and generalize findings. We thus investigated the feasibility of generating structured motivational messages tailored to mood, self-efficacy, and progress. For this, we compared the perceived motivational impact of our generated tailored messages to the one of generic messages written by experts in health psychology and coaching based on an online study with 60 participants. Moreover, we thematically analyzed what people find motivating and demotivating in motivational messages for physical activity coaching. Read our paper here: https://doi.org/10.3389/fdgth.2023.1215187.