In Texas, if the income of my wife and I for the purposes of Obamacare is $15,000 I get zero subsidy. But if it is $16,000 I can get an annual subsidy of over $11,000. The income taxes I would need to pay on the additional $1,000 is a trivial amount compared to the value of the $11,000+ insurance subsidy.
In fact, if my income were $0 the taxes I would pay for $16,000 in income are less than the insurance subsidy.
Great, you say. If I could manufacture income out of the air I wouldn't need Obamacare. Actually, "manufacturing" income may be easier than you think and does not involve making $67.89 per hour on the internet or generating spam.