An airplane will humble you. Not too terribly long ago I made a big mistake of trusting the (reported) weather. Clouds reported bottoms at 8800 and tops at 9500. I was in Bozeman and needed 11k to get over the hills IFR. Temp was a few above freezing at 10 so I figured I should be ok. Hit 9500 and wasn't out of the clouds (I filed 13) kept climbing and didn't think about the temperature dropping as I was still in the clouds. I hit 13 and was still in the clouds - Skywest not 10 miles said tops were 14, so I asked for 15. It was right around freezing now but I still wasn't picking up ice. All the sudden it started raining (freezing rain) and the airplane literally stopped climbing. I was right at 14 and it would not go any higher. (I was in a T182) I had radar, it didn't show anything and it caught me totally by suprise. I told ATC I needed to go down NOW - I was out of the mountains (ish) and landed at Billings to collect myself. It was 55ish on the ground and I still had ice on the plane.
After that I told my boss if it was within 10 degrees of freezing and flying in IMC neccesitated the flight, I wouldn't do it. I told him if he didn't like it he could get me a more capable airplane - we haven't had to cancel any trips yet but that was last spring. He's not gonna be happy with Winter around the corner when I stop flying.