mhoran mentioned PMI. One can look at a PMI encumbered loan this way: the rate on the loan is the mortgage rate for the lower 78% of loan to value. The rest of the loan has a true rate that has to include the PMI cost. Mathematically, it's as if you had two loans, a fixed rate, and a high priced second mortgage. If the $20k you need to pay down to eliminate PMI has a monthly $100 cost, the rate on that money should be viewed as 6% above the mortgage rate you already pay.
A credit card with too high a utization can ding your credit score short term. Regardless of total utilization.
Aside from these two issues, adjust the rates for taxes, eg my 3.5% mortgage is really 2.6%, and stick with the plan to sort by rate to pay off.
Too many expensive mistakes are made based on emotion. If you have the discipline of a mathematician go with the numbers. Keep in mind, millions 'feel' good about a tax refund. When anyone tells you they got a big refund, they are bragging they planned poorly, lent the government money interest free, and are too ignorant to understand either point. I always respond "that's great" and fake a smile.
The debt snowball method is a cult that may provide an emotional win. No mathematician should belong to that cult.