Most of the time, success is defined by how financially stable you are and also how you can maintain that financial position, and people do say that "you never know the true colour of a human till he/she tastes wealth" and this is because people believe a poor individual will usually be on their best behaviour, the humble stage, always trying to give you the attention you need because you are in his league but when money comes, he will be forming busy or unavailable, well it is both true and untrue as the same time. The truth aspect is that we all have this change within us and it isn't something you can help or prevent, it also depends on how you train yourself. Most rich people tend to forget those that they start the humble beginning with, it isn't because their new state is intoxicating or because they tend to look down on you but because you didn't work on yourself while they were working on themselves. I once heard the statement "When I was struggling or working on myself, what were you doing".
One reason you think they change is because you are trying to project yourself on them, people say, no one own you anything and likewise you don't own anyone anything. Fine you help them one way or the other out of loyalty perhaps or you were there for them in their times of need and suddenly they hit that breakthrough, most don't just change immediately, a reasonable friend will try to pull you up too but it depend on whether you want to be pulled and if nothing positive is coming, that is when they start acting busy, not picking your calls or won't want to see you.
On the other part, once you are successful financially, people don't see you the same again because you are now an opportunity or a resource to them, something they can thrive on, someone they can always depend on or run to for help and there is this pattern in my country and it is very common, once you render help to someone, they always expect you to keep rendering the help anytime they come to you for help. A woman once asked me for advice and for some minutes, I didn't know what to say to her, she wasn't that rich per se but she is ok in her own little way and one thing I admired about her is that she loved helping people whenever she can and there is this particular woman she had helped multiple times. Just like they use to say, Money comes and money goes, this woman (the helper) was in her broke period and the woman she use to help came as usual for help but she couldn't render it and also didn't know what to say to the "helpee" and I had to tell her to inform the helpee that she can't render any help during that period, some helpee might interpret it as pride, if she won't help, someone else will blah blah blah, that is how some people feel if their financial stable friend can't help.
We never know what they might be going through, it is easy to be rich overnight but maintaining that position requires a lot of works, why do you think the rich don't move with the poor and always decide to stay with the rich gang, they believe they will find more business opportunities, connections, mutual benefits etc but if they decide to roll with someone below them, they may likely become the prey to be fed on.
This is very true. Success changes not just the individual but also how people around them see and treat them. I like how you pointed out that it’s not always pride but sometimes a shift in priorities and expectations. I like your post