Many people look forward to retirement, so much so that they actively spend their days counting down the time until they're ready to say goodbye to their careers for good. But while you may be excited about the idea of retiring, once that happens, you could easily get thrown for a loop. Here are a few reasons you might end up unhappy in retirement -- and what to do about them.

1. Not having enough money

It's never comfortable to feel squeezed financially. And if money ends up being tight during your senior years, that alone could be a reason to dislike your retirement lifestyle.

A person at a laptop leaning their head against their hands.

Image source: Getty Images.

Now unfortunately, one factor you can't control is inflation. The cost of living might rise at a faster pace than you expect it to, and that could put you in a financial crunch.

But a good way to avoid financial struggles in retirement is to build yourself a solid nest egg. And starting early could be the ticket to amassing a nice 401(k) or IRA balance over time.

If you sock away $300 a month in your retirement plan and your investments average an 8% annual return (which is a bit below the stock market's average), you'll end up with $263,000 after 25 years. But if you give yourself 35 years to save, you'll end up with a nest egg worth $620,000, all other things being equal.

Another good way to avoid a financial crunch in retirement? Know what to expect from Social Security. You can create an account on the Social Security Administration's website and use it to access a copy of your most recent earnings statement. That should give an estimate of your monthly benefit so you know how much income to anticipate.

2. Not having enough to do

It's hard to go from working full-time to suddenly having nothing to fill your days with. And if money ends up being tight, your options for staying occupied may be limited.

The solution here is twofold. First, push yourself to save as much money as possible for retirement so you have more options for staying busy. But also, get creative when it comes to finding ways to occupy your days on the cheap.

Find a place to volunteer, or sign up for low-cost activities at your local community center. You can also do things like start a book club that meets at your town library, which will give you a gathering to look forward to and a task to tackle in between meetings.

Many retirees struggle socially in the absence of reporting to work. So it's good to find activities that not only keep you busy, but have you engaging with other people.

3. Not having enough structure

Some people thrive on a steady routine. So even if you have enough money to travel and stay busy in retirement, you might struggle due to a lack of structure.

The solution? Know yourself, and put yourself on a schedule from the start. Have a set time when you'll get up in the morning, plan your meal times in advance, and commit to doing certain activities, whether it's grocery shopping, gardening, or reading, at preset times.

The last thing you want to do is work hard to be able to retire only to find yourself miserable. But if you take steps to address these issues, you can avoid some of the struggles so many seniors end up grappling with.