I think the use of the words "hard work" is clouding people's replies. It's easy to wonder if it's really worth the effort when there's been a period of bickering, arguing, taking each other for granted, sleepless nights, work commitments and a million and one other things that encroach on normal life. No-one is perfect and we all need things sometimes that is just for us without having to consider another person.
There will be times when you aren't in the same place emotionally, or physically, and you will clash and butt heads. There will be times when one of you thinks you have done something nice but the other will be upset or massively irritated by it. Times when you clash over views or basics. All of this stuff can make you think "this is hard work" and wonder if it's worth the effort. The person you marry won't necessarily be the same person 2, 5, 10 years later. We all grow at different rates and our personal journey may or may not include the person you fell in love with. Outside influences also play a huge part in your personal journey.
We have been very happily married 32 years next week, and have been together for 36 yrs. There have been periods in our life that have been turbulent. We have had screaming rows, dissatisfaction with ourselves and each other, periods of personal growth that doesn't coincide with each other's. Times when we haven't been able to connect emotionally, periods of bickering and taking each other for granted. But those times are few and far between and we have communication, a mutual respect and love, and if I woke up tomorrow and he wasn't here I would be bereft.
I think the question you need to ask yourself is "am I here because I want to be". If the answer to that is yes then, with communication and making time for each other outside the daily chaos, you can work through the difficult times. The ability to support and accept another persons idiosyncrasies, emotions, fears, dreams and personal goals without losing yourself is a skill to be learned together.
Those people saying they don't understand what you mean by "hard work" are just being pedantic. There are very few couples who can go through life together without, at times, feeling hurt, unappreciated, and distant. We are human after all and our needs are never the same as someone else's no matter how much you love them.
A bit like me saying my teenagers are a doddle, as children they were easy and life with them has been a complete joy from then till now. Always slept, always ate, never tantrummed, always respectful, a delight now they are older. Most would roll there eyes and say "yeah right".... it's the same with marriage.