I understand the temp/dew point spread issue with safety. Usually this just results in a delay for a morning flight while waiting on temp to increase. The main thing that has given me grief is the 5 knots or less crosswind and 15k or less total wind, and no gusts. Most of my dual was in wind conditions that weren't allowed once I was solo, so fortunately I got a lot of practice in those conditions, which have benefitted me, but now that I am solo, it seems a bit restrictive at times. There have been a lot of days lately with, say a 16 knot down the runway wind: can't solo. 6 knot crosswind: can't solo.
Not complaining, as I totally understand the safety reasons for these restrictions, but it is still frustrating to cancel when it is conditions I have successfully dealt with, and feel comfortable with.