Ask me again in a few years when I have achieved something!

If you want to read a thread that explains my view in detail, read this thread here: http://www.gamedev.net/topic/664743-i-am-beginning-to-hate-the-it-and-gaming-industry/ . Although I still disagree about most of the advice given to me, YMMV, so don't take my word for it.

I posted about this before, so rather than rewrite it, you can read about it in detail here: http://www.gamedev.net/topic/667026-from-scratch-vs-unity/#entry5219758

Thanks for the link.. I will definitely read them

Software fundamentally works the same way. You can be working on business database software, or weather simulations, or game engines, or stock market prediction tools, all of them are fundamentally working on the same principles.

Computer science courses teach a core group of fundamental algorithms and data structures.

Boiled down and distilled into their essence there are only two fundamental data structures: sequential memory (the array) and linked memory (most easily viewed as a linked list or tree). Coupled with a small collection of algorithms there are around 15 common data structures made by re-interpreting the two fundamental structures, such encoding trees or heaps into sequential memory or building binary trees in linked memory. This small core set is constantly being adjusted and specialized for different behavior, but deep down they are the same patterns.

There are similarly a small set of core algorithms in various topics: numeric manipulation, sorting/searching, graph manipulation, syntactic manipulation, and combinatorial manipulation. A small set of fundamental numeric algorithms represent everything from 3D skeletal animation to encryption cyphers to statistical evaluation for data mining. Sorting/searching let you look up information on Google and lets Walmart scan your receipt among billions of others just like it, and in games lets you filter things down into cache-friendly sizes. A small number of fundamentals in graph manipulation lets you find paths on a map, finds the nearest match for spell checking, and routes traffic efficiently on the Internet.

Every topic, 3D graphics, 2D graphics, audio processing, AI, databases, search engines, disk controllers, real-time stock trading, point-of-sale equipment, television broadcast software, SCADA systems, all of it is an application of those core algorithms and data structures.

I never know that. Thanks for explaining this.

Not necessarily.
If you've never driven a car, can you be expected to design a car from scratch which is comfortable to drive, has high performance, and is easy to maintain?
If you've never used a big engine, can you design one from scratch that's productive for users, has high performance, and is easy to maintain?
At the very least, using Unity/Unreal/etc is useful as a competitor analysis and market review! (or as a laundry list of features to consider copying )

Also, the quality and impressiveness of a project isn't determined by which technology it's built on top of.
Sure - if two candidates both shoe an identical FPS game, but one says they made it from scratch while the other says they used Unreal, then the first candidate is way more impressive (or is discarded for lying ).
But that's usually not how things work.

Usually the from scratch games we see are things like Mario clones, or arcade games.
The simple "engines" that are used in these projects really have almost nothing to do with big commercial engines, so it's often not at all impressive when people show off their own "engines"... especially when their "engine" has no toolchain, nor any gameplay-level helper libraries. It's often just a demonstration that they know how to glue together a few open source libraries like SDL, etc...

On the other hand, people using big engines can often talk in depth about some specific feature they implemented -- e.g. "I took a sample Unreal FPS project, and I added logic for AI formations, so that they maintain a 'V' shape while attacking you".
Doing something like this can be more impressive. Also, one of the most important skills at large companies is the ability to be able to read other people's code and quickly understand it. Often, you'll only be writing ~10 lines of code a day, but you'll be reading thousands of lines of other people's code. If you only ever work on projects from scratch, then I guarantee you that you'll be terrible at this when you start out as part of a large team. By working with something like Unreal 4 and adding new features to their engine, you'll be practicing something that's a lot closer to what a real engine programmer's job looks like!
There's no rule here either way. Both are a chance to show off your coding style and range of abilities. Both options handicap you in different ways.
If you have time, do some projects from scratch, make your own engine, make some projects using the big popular engines, and make some mods. Do everything!

Thanks for giving me an insight on how game companies work( i mean hire someone new). This has change my view.

The response on this thread is amazing. Thanks everyone.

This is an open ended question so feel free to share your experiences and story. In this world full of competition especially on game dev since theres a lot of talented people out there, its easy to loose motivation. Maybe by sharing what youve done in the past can inspire others :D

I do read a lot of thread here most of the time so i always check my thread :D.

This will definitely help a lot of newbs out there who also aspire to get into game dev just like me.