Not to get anyone in a defeatist state of mind…I’ve enumerated these before but indulge me and let me explicitly list these. Now I’ll be more accountable when I’m tempted to break one of these. 
1.) Never end a workout during a recovery period. Always start the next interval. If you need to get off the bike and walk around a little bit, great, but always get back on and start the next interval.
2.) Never start an interval at less than 100% of workout intensity.
3.) Always try to make it half way through the interval at 100% intensity.
4.) Never reduce intensity by more than a few percent. Give it at least 30 seconds. A minute is better.