Just some observations without any specific admissions:

1. It's best when hopping up on to a curb or ice shelf to do so at right angles

2. Chain suck can really suck

3. When railroad tracks run through streets, sometimes the space between the track and the pavement is just wide enough to grab a wheel pretty good.

4. The above railroad tracks can be really slippery when wet

5. A little bit of water on a sharp turn at the bottom of a steep hill can turn a street into big slip-'n slide