Sure, riding in the hot sun and putting in efforts can be a task. But, that’s no reason to scowl. Scrunching your eyes from the glare/ while focussing on the road is one thing, but once you are off the saddle turning that scowl into a smile will not only put you in a better mood, but it will encourage people to talk with you and be friendly towards you. It could also help newcomers feel welcome and comfortable in the group.