Whether we choose to think about it or not, humans in their daily lives directly cause immense suffering to the little creatures. Leaving them half crushed, spraying poison, drowning. Have you ever observed these events closely, and possibly worsening the situation for the insect: tear off a leg, peel a wing?
When I was little I did it once and felt horrible. Now days I don’t really think about avoiding them, but my policy tends to be don’t annoy me I don’t annoy you