I don't think I've ever decided later that going was a mistake. I've come home comfortably hot, cold, or wet and sometimes discouraged concerning my lack of success, but never sorry I went.
Yesterday I had almost decided to cancel my plans to fish the upper Patuxent between the reservoirs because the forecast was for the mid 90's and I was already hot after my morning old guy exercises, but I happened to glance at the thermometer shortly before 11 and it hadn't hadn't reached 80 degrees yet. What the hell, it would only be a 20 minute drive and I could always return.
A half an hour later under the shade of the stream-side trees, I was standing in the cool water just over my ankles catching fish: two small bass on a B&B and about a half dozen fallfish when I went deeper with a crystal bugger. It's a small stretch of water, so I was finished with it in just over an hour.
Looking back on the week, Monday I caught almost nothing and yesterday it was mostly something commonly called a "trash fish", and yet I returned both times satisfied with good memories of the day.