What kit do you consistently use that has a design flaw that winds you up?
Recently purchased a new road helmet (Spec S3 - My first helmet that I use just for the road). The blooming chin strap reverberates really really loudly above 30mph. Have to hold my mouth open to get it to stop. Drives me crazy. And my glasses don't stay in the vents when I take them off mid-ride, grrrrr. First world problems.