McLaren only finished third in the constructors' standings despite having the pacesetting car at several junctures this season, while drivers Lewis Hamilton and Button had to settle for fourth and fifth in a championship both had led at times.
Although the team had several well-publicised technical failures and pit delays, Button believes the spells when McLaren was too slow to fight for wins should not be underestimated.
"Sometimes you do get failures and you've got to rectify the issue," he said.
"But the most difficult part for us was before the summer break when we just didn't have the pace.
"The reason why we were not fighting for the title isn't just the reliability issues, the pace in that period of time wasn't good enough compared to our competitors."
He feels the mechanical glitches attracted more attention due to their timing.
"We have had reliability issues, but when you actually look at it, the problems have all been at weekends," Button said.
"We did 1400 kilometres at the young driver test and didn't have one issue at all, so we have been a little bit unlucky, I think."
From May to July, Button endured a string of races where he could manage no better than lower top-10 places, but he thinks the team ultimately benefited from his difficulties.
"We tried new things because I struggled to get tyre temperature more than most, and it didn't work, it just destroyed the tyres around Monaco and Canada time," he explained.
"Lewis had a good race in Canada and I had such a bad race, and it was good for the rest of the year in a way because we had the two extremes so we could look at the data, get in the simulator, change the balance around, and work out why I had so much degradation and he didn't.
"It was really useful to learn what you can and cannot do with the tyres, because it's different to what you'd usually think."
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