After I do my workout at the gym, I go straight home.
But when I see someone dutifully always doing their stretches after working out, I am impressed.
ご質問ありがとうございます。
"After I do my workout at the gym,"=「ジムで筋トレをした後」
"I go straight home."=「まっすぐ家に帰ります。」
"But when I see someone dutifully always doing their stretches after working out,"=「でも筋トレした後に、ちゃんといつもストレッチをしているのを見ると」
"I am impressed."=「関心します。」
ご参考に。