Other claims rejected by HM Revenue and Customs (HMRC) included a wasp causing an accident and a child scribbling on the forms.
Self-assessment returns are generally required from the self-employed and those with multiple sources of income.
The next deadline is for online returns, which falls on 31 January.
About 10 million people are in the self-assessment system, and returns up to three months late incur a fine of at least £100.
The deadline for paper returns was on 31 October. Among the excuses for failing to file was: "A wasp in my car caused me to have an accident and my tax return, which was inside, was destroyed."
Another claimed: "My wife helps me with my tax return, but she had a headache for 10 days."
Blaming a husband or wife also featured in excuses such as: "I could not complete my tax return, because my husband left me and took our accountant with him. I am currently trying to find a new accountant."
Others used the oldest excuses in the book. "My dog ate my tax return... and all of the reminders," one claimed.
"It is easy to see that some excuses for not completing a tax return on time can be more questionable than others. Luckily, it is only a small minority who chance their arm," said Ruth Owen, HMRC director general of customer services.
"There will always be help and support available for those who have a genuine excuse for not submitting their return on time."
Excuses from individuals who failed to submit their tax return this year included a claim that the paperwork was engulfed in a yacht fire.