With anything in life it takes a long time to become good at something. Whether you're in school for a degree, mastering a skill, or practicing for a sport. These all take a large amount of time and practice in order for you to accomplish your goal, or to improve at them. Fitness is the same way, yet many will give up after the first month if they aren't seeing the results they want. It's said that our society today is obsessed with instant gratification, and when it comes to results in terms of your body and fitness, this certainly seems to be the case.
You don't become overweight in a matter of a few weeks, it's the same when it comes to being muscular, ripped, or having a physique you're proud of. For example, most professional bodybuilders today are closer to 30-40 as opposed to 20. This is an extreme case, obviously not everyone wants to look like a pro bodybuilder, but it reinforces the fact that it takes a long time to build that level of muscle mass. Competitors will usually diet up to 20 weeks for a bodybuilding competition to look their best on show day. Practically half of a year is dedicated to them trying to make their physique look the best they can.
If you're not willing to put the time and work into the process then you'll never be happy with your fitness journey and will eventually end up quitting. Not to mention that losing the last few lbs you're carrying can take even longer than the rest of the weight you lost previously. You can't expect to be able to play in the NFL, become a concert pianist, or earn your PHD in a few weeks, so don't expect to have the dream body you've always wanted after a month of eating healthy and exercising. Instead you should enjoy the process, learn what type of exercise you enjoy and the healthy foods you like to eat and stay disciplined towards your goals. If you're consistent the results will come.