Great, because I do as well.
Let me elaborate before you start thinking I'm a rogue personal trainer who makes her clients follow programs but doesn't follow one herself. I follow a structured exercise program and within that program I schedule a 'fun cardio workout' because one of my goals is to maintain a solid cardiovascular fitness level. On this particular day, I like to pick a conditioning workout from some of my favourite fitness trainers, such as Megan McDermott, Katie Crewe or Jenna Louise. The only goal of this workout is to have the above mentioned 'fun cardio workout' and this is how I do that. I find these workouts keep my training interesting and makes me more motivated to get it done because it's exciting to try new things.
That being said, the rest of my training is quite routine because I have other, individual, performance goals that I prioritise on top of my cardio goals and my structured program specifically caters to that. Do you see where I'm going with this? The bold font might give it away...
If your goal is to do a fun, diverse workout each day and just move; keep doing your Instagram inspired workouts - there's nothing wrong with that... if that's your only goal. Now, if you are someone who has specific strength goals, doing a different workout every day won't get you there because strength is gained through structured consistency. This requires commitment (a commitment made easier if you schedule a 'fun day' for yourself like I do and you don't feel bad about deviating from the program because it was already on the program *this is where I would insert a wink emoji if they didn't have such a creepy stigma around them*) beyond doing random workouts and following a personalised program.
There are so many benefits to following a program:
A. Personalised programs are based on individuality:
Every body moves differently and we all have different strengths and weaknesses. For example, I have a few clients who want to achieve their first push up. For some clients, I'm able to incorporate skill work (e.g. incline push ups) into their training straight away while other clients may need to do more isolation work (e.g. strengthening their plank or building their tricep strength a bit more) before we move on to the skill work. Although they have the same goals, their training differs.
B. Programs are specific to your goals:
Sure, all my clients have strength and performance goals but to some clients strength means being able to deadlift their own bodyweight and for other clients, strength means doing five pull ups in a row. Their programs are specific to their own goals.
C. Your body adapts to your consistent efforts (e.g. you get stronger) so your program incorporates progressive overload:
As you get stronger, your program is scheduled to continue to challenge you in order for you to keep progressing. This can be done through increased intensity or volume.
I hope that these reasons are enough to convince you of the importance of consistently following a program. I think there are heaps of great ideas and useful content on Instagram to give you inspiration for exercises (for example, hinging and squatting variations) but don't go crazy on variety and remember consistency is key to achieving your strength and performance goals.