Adapted from a recent online discussion.
Truth be told: Being yourself is what's most important
Q: Can a person want to change because s/he wants to make the other person happy? In other words, if someone loves you, should they be willing to compromise and/or change things (assuming you're willing to follow through on your own things)? I don't know. I'm confused.
A: How much you change is up to you. If you want to change to please someone you love, go for it (though it's usually a terrible idea). But just because you're willing to change doesn't mean the other person then "owes" you a commensurate change as proof s/he loves you back.
Often the most loving gesture is not trying to change to please someone. There's an honesty to it that allows the other person to make a free and fully informed choice on whether to stay or go. So I would say that if you love someone, and you have an area in which you aren't compatible, it's best to be emotionally true to yourself.
I'm not arguing for rigidity. If you have some growing up to do, then, by all means, use this situation as the butt-kick you need to be more mature about your behavior and expectations. Similarly, if you come across an area where change would be good for you even if this person weren't in the picture anymore, then certainly don't resist change just because it started as a change "for" someone else.
If on the other hand the incompatibility is in an area where change would be grudging, unnatural or unrealistic, then it's better for all involved to say — for example — "I'm an introvert. I'm never going to flourish while going out a lot, or hosting a lot of people, or networking for your job."
This is true even if you're willing to push yourself a bit beyond your comfort zone on someone's behalf. It's only fair for it to be clear you're not a whole new improved person, you're just the old person working really hard. Because you'll never be a natural and eventually you're going to get tired, something your mate should know and expect.
Suggest change, but accept the results you get
Q: Re: Changing:
I think a distinction should be made between qualities a person really can change (being late, being messy, etc.) and qualities that are fundamental to a person's personality and are very unlikely to change (being an introvert, not being funny, etc.).
A: Actually, the only helpful distinction to make is between the things someone actually does change, and doesn't. Plenty of tardy slobs choose not to clean up or show up on time.
Certainly when something bothers you about a mate and you think the mate might want to know you're upset, you can and should speak up. Chronic lateness is a perfect example.
But the key next step is to be unflinching in your acceptance of the results. If speaking up once doesn't work, then you don't just escalate to nagging, to begging, to silent treatments. You take your answer and you decide if you can accept this person as-is, or not.