Most people probably imagine retirement as one of the happiest times of their lives. After working for decades on end, you finally get the chance to sleep in, travel the world, spend more time with the grandkids, or whatever else you want to do.

For some seniors, though, retirement isn't all it's cracked up to be. In fact, about 28% of them say their lives are actually worse during retirement than before they left the workforce, according to a Nationwide survey.

Is that a depressing thought, or what?

Confused and frustrated man looking at documents

Image source: Getty Images.

The good news is that the reasons people gave for being unhappy with retirement were largely financial -- and therefore preventable. Of the 28% percent of retirees who are unhappy, 78% cited income as a reason, and 76% blamed an increased cost of living.

The study also pointed out that there's a disconnect between expectations and reality for many unhappy retirees, particularly because they overestimate how much they'll receive in Social Security benefits and underestimate how much they'll pay in healthcare costs.

Insufficient income and rising healthcare costs can quickly ruin retirement for anyone, but with a little planning, it's possible to avoid these issues so that you can truly enjoy your golden years.

Social Security: Plan more, expect less

Over half of people aged 50 or older expect to see cuts in Social Security benefits in the coming years, according to the survey -- and some form of benefit cuts looks more likely by the day.

By 2034, the Social Security Administration is expected to have depleted its asset reserves, barring intervention from federal lawmakers. While that doesn't mean the program will come crashing down in the next 15 to 20 years, it does mean the program won't be able to sustain benefits at the levels it has promised. According to a recent report by the Social Security Board of Trustees, in order for the program to remain stable over the next 75 years, benefits will likely have to be cut by about 23%.

So what can you do about this? Start by lowering your Social Security expectations. For 61% of retired Americans, Social Security makes up at least half of their income -- and for unmarried retirees, that number jumps to 71%. These are the people who will be hit the hardest if (or when) benefits are slashed.

One of the best ways to avoid getting burned by Social Security cuts is to continue working as long as you can. While it's probably not the advice you wanted to hear, if you wait until age 70 to claim benefits, you'll get a 24% to 32% bonus tacked on to your monthly checks thanks to the program's delayed-retirement credits. So even if benefits are cut by 23%, you'll still be earning close to your full benefit amount, if not more.

On top of that, working a few extra years will allow you to keep padding your retirement account, rather than drawing it down to cover your expenses. Then you'll be less reliant on Social Security in the first place.

Medicare: What it does (and doesn't) cover

Aside from a lack of income, many retirees are also upset about their high cost of living -- particularly in regards to healthcare costs. Much of this comes down to confusion surrounding Medicare.

Medicare will cover a lot of your healthcare bills, but it doesn't cover everything. You'll still be responsible for the copayments, coinsurance, and deductibles, and Medicare won't cover most dental care, routine eye care, hearing aids or exams, routine foot care, or long-term custodial care (such as a nursing home).

This can come as a shock to anyone who was expecting healthcare to be free once they became eligible for Medicare. These costs add up quickly, and they can wipe out a retirement fund if you're not prepared.

To make sure you are prepared, you have a few options. You can open a health savings account (HSA), which allows you to invest pre-tax dollars and then withdraw them tax-free to spend toward qualifying medical expenses, such as deductibles and other out-of-pocket costs. And once you turn 65, you'll no longer face the 20% penalty for making non-medical withdrawals -- so your HSA essentially becomes another retirement fund.

There are also government-sponsored ways to get help paying your healthcare bills, such as Medicaid and state Medicare Savings Programs. If you qualify for either of these programs, you may receive financial assistance to help cover medical costs, deductibles, premiums, coinsurance, copayments, and prescription drug costs. While the best option, of course, is to try to save enough so that you don't have to rely on assistance programs, if you know you're going to fall short financially when it comes to healthcare, know that you do have options.

Retirement should be a joyous time in your life, and nobody wants financial problems to stand between them and a happy retirement. Fortunately, they don't have to. With a little pre-retirement preparation, you can make sure your golden years are everything you'd hoped for.