One of the qualities and vices of the entrepreneur is impatience. It is a quality, because too much patience means that nothing will ever happen. A buddha-like, infinitely patient entrepreneur will simply wait for someone else to scratch that itch, rather than roll up his sleeves and get it done himself. Infinite, god-like patience is not compatible with being an entrepreneur.
At the same time, too much impatience is a problem. Things take time. A lot of time. Ridiculous, unacceptable amounts of time. We can use impatience to make them happen a bit faster, but there are limits. Too much impatience breeds discontent, unhappiness, demotivation, all because of unrealistic expectations.
This is true in all areas of life. People who take up a new diet or exercise regimen often expect results within days. The reality is, though you might feel better right away when you start exercising, tangible, lasting results typically take 6 weeks or more to appear for good. New habits take 30 days or more just to become habits, let alone to make a lasting difference to your life. Some benefits might be visible right away, but most take much longer. Reading a new self-help book or article won't instantly make you better - it takes time and perseverance, sustained effort over a period of time that, for the impatient man, is excruciating.
Learning to be a successful entrepreneur takes years. Building a profitable business takes similar amounts of time. There are shortcuts that can speed this up. If you have a great, hands-on mentor, perhaps things can go a bit faster. If you have a great salesperson on a roll, maybe the business can be profitable from year one. If you're very experienced, have a top team ready, and you know exactly what you're doing, maybe it can happen even faster.
Most of those shortcuts, though, are not really within our immediate control. This means building a successful business will take a lot more time than entrepreneurs have patience for. So get ready for a frustratingly slow pace of progress, and make sure that psychologically as well as financially, you're in it for the long term.
The longer term view
There are a number of consequences, in terms of your mindset and decision making, to taking a long term view rather than being focused on a short term outcome.
The first is that you are more willing to invest in learning things that can help you go faster over the long run. One of the symptoms of a short-term mindset is the feeling that you just don't have the time to learn new things, because you need to just get things done. While there is certainly a point where you should stop using "I don't know enough" as an excuse for getting things done, there should never be a point where you tell yourself "I don't need to learn anything anymore, I know enough already, I should just do things". That's swinging into the opposite and equally harmful extreme.
Another effect is that you start to make choices that offer the short term benefits you want, but that don't screw you in the long term. For example, you will pick technologies that are there for the long term, and you will avoid accumulating large amounts of technical debt. On a business side, you would make sure deals you make don't impose unreasonable long-term costs in exchange for short-term benefits (by for example tying long-term obligations to short-term results).
Another effect of being an entrepreneur for the long term is to take time to grow as an individual, both in terms of what you know (covered earlier under 'learning'), and in terms of who you are and who you know. Investing time to get to meet interesting people, or taking the time to teach others what you have learnt, may seem like a waste of time from a purely short-termist point of view. But those are all valuable things if you plan to be around for the long run.
There are always exceptions to every rule, always counter-examples that show that you don't have to do it this way. You will certainly find examples of people who got into startups, spent a handful of years building a company with a lot of focus on the short term, then exited and never thought of the topic again. But those are exceptions (and were, in many cases, exceptionally lucky). If you want to maximise your chances of becoming a successful entrepreneur, you need to realise that it will take years, perhaps even a decade, and make your decisions accordingly.
If you read this far, you should follow me on twitter here.