... he makes an excellent point.
He has been going through a tough time with his poor Mum being so ill, but his ten-minute exercise streaks have kept him going, even though he has had to start over several times this year.
I feel the same way about my Mile with Leslie Sansone streak (currently day 254). I've been luckier than Spark Guy, in that I haven't missed a day since I started on my 50th birthday, because even on my worst days I've managed a mile, which can be anything from 12 minutes to 20 or so, depending on warm-ups, cool downs and stretches.
Some days I've scraped one mile and been pleased to manage that much, because it was quite an achievement, given my state of health at times. Other days have seen me manage up to 5 miles, or I've included other exercise, such as using the Wii, walking into town, and gardening.
The point is, that as long as you have a personal baseline goal that you can manage reasonably easily, that is not unrealistic given your current state of fitness, you are far less likely to fail, and if you do have a stumble, for whatever reason, it isn't such a difficult thing to get back up and start again.
One other thing you notice over time is that, even with the odd blip, your streak days when added together far outnumber the days you couldn't manage to stay on track.
You don't fail on an off-day as long as you get back up and start again.